Release v1.6.0 (#324)

* Update version and changelog for v1.6.0
* Update docs
diff --git a/docs/dyn/cloudbuild_v1.projects.builds.html b/docs/dyn/cloudbuild_v1.projects.builds.html
index 1ab68eb..8ae8b6e 100644
--- a/docs/dyn/cloudbuild_v1.projects.builds.html
+++ b/docs/dyn/cloudbuild_v1.projects.builds.html
@@ -130,6 +130,9 @@
     "status": "A String", # Status of the build.
         # @OutputOnly
     "finishTime": "A String", # Time at which execution of the build was finished.
+        #
+        # The difference between finish_time and start_time is the duration of the
+        # build's execution.
         # @OutputOnly
     "timeout": "A String", # Amount of time that this build should be allowed to run, to second
         # granularity. If this amount of time elapses, work on the build will cease
@@ -157,7 +160,7 @@
         "A String",
       ],
     },
-    "createTime": "A String", # Time at which the build was created.
+    "createTime": "A String", # Time at which the request to create the build was received.
         # @OutputOnly
     "id": "A String", # Unique identifier of the build.
         # @OutputOnly
@@ -186,6 +189,9 @@
         "commitSha": "A String", # Explicit commit SHA to build.
       },
     },
+    "buildTriggerId": "A String", # The ID of the BuildTrigger that triggered this build, if it was
+        # triggered automatically.
+        # @OutputOnly
     "steps": [ # Describes the operations to be performed on the workspace.
       { # BuildStep describes a step to perform in the build pipeline.
         "waitFor": [ # The ID(s) of the step(s) that this build step depends on.
@@ -197,10 +203,9 @@
         ],
         "name": "A String", # The name of the container image that will run this particular build step.
             #
-            # If the image is already available in the host's
-            # Docker daemon's cache, it will be run directly. If not, the host will
-            # attempt to pull the image first, using the builder service account's
-            # credentials if necessary.
+            # If the image is already available in the host's Docker daemon's cache, it
+            # will be run directly. If not, the host will attempt to pull the image
+            # first, using the builder service account's credentials if necessary.
             #
             # The Docker daemon's cache will already have the latest versions of all of
             # the officially supported build steps
@@ -284,8 +289,7 @@
     "images": [ # A list of images to be pushed upon the successful completion of all build
         # steps.
         #
-        # The images will be pushed using the builder
-        # service account's credentials.
+        # The images will be pushed using the builder service account's credentials.
         #
         # The digests of the pushed images will be stored in the Build resource's
         # results field.
@@ -336,6 +340,9 @@
   "status": "A String", # Status of the build.
       # @OutputOnly
   "finishTime": "A String", # Time at which execution of the build was finished.
+      # 
+      # The difference between finish_time and start_time is the duration of the
+      # build's execution.
       # @OutputOnly
   "timeout": "A String", # Amount of time that this build should be allowed to run, to second
       # granularity. If this amount of time elapses, work on the build will cease
@@ -363,7 +370,7 @@
       "A String",
     ],
   },
-  "createTime": "A String", # Time at which the build was created.
+  "createTime": "A String", # Time at which the request to create the build was received.
       # @OutputOnly
   "id": "A String", # Unique identifier of the build.
       # @OutputOnly
@@ -392,6 +399,9 @@
       "commitSha": "A String", # Explicit commit SHA to build.
     },
   },
+  "buildTriggerId": "A String", # The ID of the BuildTrigger that triggered this build, if it was
+      # triggered automatically.
+      # @OutputOnly
   "steps": [ # Describes the operations to be performed on the workspace.
     { # BuildStep describes a step to perform in the build pipeline.
       "waitFor": [ # The ID(s) of the step(s) that this build step depends on.
@@ -403,10 +413,9 @@
       ],
       "name": "A String", # The name of the container image that will run this particular build step.
           #
-          # If the image is already available in the host's
-          # Docker daemon's cache, it will be run directly. If not, the host will
-          # attempt to pull the image first, using the builder service account's
-          # credentials if necessary.
+          # If the image is already available in the host's Docker daemon's cache, it
+          # will be run directly. If not, the host will attempt to pull the image
+          # first, using the builder service account's credentials if necessary.
           #
           # The Docker daemon's cache will already have the latest versions of all of
           # the officially supported build steps
@@ -490,8 +499,7 @@
   "images": [ # A list of images to be pushed upon the successful completion of all build
       # steps.
       # 
-      # The images will be pushed using the builder
-      # service account's credentials.
+      # The images will be pushed using the builder service account's credentials.
       # 
       # The digests of the pushed images will be stored in the Build resource's
       # results field.
@@ -644,6 +652,9 @@
     "status": "A String", # Status of the build.
         # @OutputOnly
     "finishTime": "A String", # Time at which execution of the build was finished.
+        #
+        # The difference between finish_time and start_time is the duration of the
+        # build's execution.
         # @OutputOnly
     "timeout": "A String", # Amount of time that this build should be allowed to run, to second
         # granularity. If this amount of time elapses, work on the build will cease
@@ -671,7 +682,7 @@
         "A String",
       ],
     },
-    "createTime": "A String", # Time at which the build was created.
+    "createTime": "A String", # Time at which the request to create the build was received.
         # @OutputOnly
     "id": "A String", # Unique identifier of the build.
         # @OutputOnly
@@ -700,6 +711,9 @@
         "commitSha": "A String", # Explicit commit SHA to build.
       },
     },
+    "buildTriggerId": "A String", # The ID of the BuildTrigger that triggered this build, if it was
+        # triggered automatically.
+        # @OutputOnly
     "steps": [ # Describes the operations to be performed on the workspace.
       { # BuildStep describes a step to perform in the build pipeline.
         "waitFor": [ # The ID(s) of the step(s) that this build step depends on.
@@ -711,10 +725,9 @@
         ],
         "name": "A String", # The name of the container image that will run this particular build step.
             #
-            # If the image is already available in the host's
-            # Docker daemon's cache, it will be run directly. If not, the host will
-            # attempt to pull the image first, using the builder service account's
-            # credentials if necessary.
+            # If the image is already available in the host's Docker daemon's cache, it
+            # will be run directly. If not, the host will attempt to pull the image
+            # first, using the builder service account's credentials if necessary.
             #
             # The Docker daemon's cache will already have the latest versions of all of
             # the officially supported build steps
@@ -798,8 +811,7 @@
     "images": [ # A list of images to be pushed upon the successful completion of all build
         # steps.
         #
-        # The images will be pushed using the builder
-        # service account's credentials.
+        # The images will be pushed using the builder service account's credentials.
         #
         # The digests of the pushed images will be stored in the Build resource's
         # results field.
@@ -860,6 +872,9 @@
         "status": "A String", # Status of the build.
             # @OutputOnly
         "finishTime": "A String", # Time at which execution of the build was finished.
+            #
+            # The difference between finish_time and start_time is the duration of the
+            # build's execution.
             # @OutputOnly
         "timeout": "A String", # Amount of time that this build should be allowed to run, to second
             # granularity. If this amount of time elapses, work on the build will cease
@@ -887,7 +902,7 @@
             "A String",
           ],
         },
-        "createTime": "A String", # Time at which the build was created.
+        "createTime": "A String", # Time at which the request to create the build was received.
             # @OutputOnly
         "id": "A String", # Unique identifier of the build.
             # @OutputOnly
@@ -916,6 +931,9 @@
             "commitSha": "A String", # Explicit commit SHA to build.
           },
         },
+        "buildTriggerId": "A String", # The ID of the BuildTrigger that triggered this build, if it was
+            # triggered automatically.
+            # @OutputOnly
         "steps": [ # Describes the operations to be performed on the workspace.
           { # BuildStep describes a step to perform in the build pipeline.
             "waitFor": [ # The ID(s) of the step(s) that this build step depends on.
@@ -927,10 +945,9 @@
             ],
             "name": "A String", # The name of the container image that will run this particular build step.
                 #
-                # If the image is already available in the host's
-                # Docker daemon's cache, it will be run directly. If not, the host will
-                # attempt to pull the image first, using the builder service account's
-                # credentials if necessary.
+                # If the image is already available in the host's Docker daemon's cache, it
+                # will be run directly. If not, the host will attempt to pull the image
+                # first, using the builder service account's credentials if necessary.
                 #
                 # The Docker daemon's cache will already have the latest versions of all of
                 # the officially supported build steps
@@ -1014,8 +1031,7 @@
         "images": [ # A list of images to be pushed upon the successful completion of all build
             # steps.
             #
-            # The images will be pushed using the builder
-            # service account's credentials.
+            # The images will be pushed using the builder service account's credentials.
             #
             # The digests of the pushed images will be stored in the Build resource's
             # results field.