Release v1.6.0 (#324)

* Update version and changelog for v1.6.0
* Update docs
diff --git a/docs/dyn/runtimeconfig_v1beta1.projects.configs.operations.html b/docs/dyn/runtimeconfig_v1beta1.projects.configs.operations.html
index 3ce5357..4c62c59 100644
--- a/docs/dyn/runtimeconfig_v1beta1.projects.configs.operations.html
+++ b/docs/dyn/runtimeconfig_v1beta1.projects.configs.operations.html
@@ -77,6 +77,9 @@
 <p class="toc_element">
   <code><a href="#get">get(name, x__xgafv=None)</a></code></p>
 <p class="firstline">Gets the latest state of a long-running operation.  Clients can use this</p>
+<p class="toc_element">
+  <code><a href="#testIamPermissions">testIamPermissions(resource=None, x__xgafv=None, permissions=None)</a></code></p>
+<p class="firstline">Returns permissions that a caller has on the specified resource.</p>
 <h3>Method Details</h3>
 <div class="method">
     <code class="details" id="get">get(name, x__xgafv=None)</code>
@@ -184,4 +187,34 @@
   }</pre>
 </div>
 
+<div class="method">
+    <code class="details" id="testIamPermissions">testIamPermissions(resource=None, x__xgafv=None, permissions=None)</code>
+  <pre>Returns permissions that a caller has on the specified resource.
+If the resource does not exist, this will return an empty set of
+permissions, not a NOT_FOUND error.
+
+Args:
+  resource: string, REQUIRED: The resource for which the policy detail is being requested.
+`resource` is usually specified as a path. For example, a Project
+resource is specified as `projects/{project}`. (required)
+  x__xgafv: string, V1 error format.
+    Allowed values
+      1 - v1 error format
+      2 - v2 error format
+  permissions: string, The set of permissions to check for the `resource`. Permissions with
+wildcards (such as '*' or 'storage.*') are not allowed. For more
+information see
+[IAM Overview](https://cloud.google.com/iam/docs/overview#permissions). (repeated)
+
+Returns:
+  An object of the form:
+
+    { # Response message for `TestIamPermissions` method.
+    "permissions": [ # A subset of `TestPermissionsRequest.permissions` that the caller is
+        # allowed.
+      "A String",
+    ],
+  }</pre>
+</div>
+
 </body></html>
\ No newline at end of file