chore: Update discovery artifacts (#1306)

## Deleted keys were detected in the following pre-stable discovery artifacts:
bigqueryreservationv1beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/6a8b3c6bd7aef8c84d5ba64410b29cabf056102b)

## Discovery Artifact Change Summary:
adexchangebuyer2v2beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/949754477e811a0b490a35e7e7313bbd22918d8a)
artifactregistryv1beta2[ [More details]](https://github.com/googleapis/google-api-python-client/commit/3811667db343c8e4ca5479b668a14b4bceddd981)
bigquerydatatransferv1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/f0071f5468eaa0320920fbee1489dbc2cb5e195f)
bigqueryreservationv1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/6a8b3c6bd7aef8c84d5ba64410b29cabf056102b)
bigqueryreservationv1beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/6a8b3c6bd7aef8c84d5ba64410b29cabf056102b)
bigtableadminv2[ [More details]](https://github.com/googleapis/google-api-python-client/commit/d1ce2408cf8bf7deaab38f7ecff96e9cb5d5a02d)
containerv1beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/60a23f0cafcca5473a829e8b11280733f76a8271)
displayvideov1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/559fa7cf4c7d300947bb556eb8c2830a751c7b11)
loggingv2[ [More details]](https://github.com/googleapis/google-api-python-client/commit/a3c1055968a4d9ac2448b0540bf4e2005be2958f)
serviceusagev1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/e2a86e92aa0ab7cce0b936a764ea5440b35a62e9)
serviceusagev1beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/e2a86e92aa0ab7cce0b936a764ea5440b35a62e9)
diff --git a/googleapiclient/discovery_cache/documents/bigtableadmin.v2.json b/googleapiclient/discovery_cache/documents/bigtableadmin.v2.json
index 2d7aa8a..c56d93a 100644
--- a/googleapiclient/discovery_cache/documents/bigtableadmin.v2.json
+++ b/googleapiclient/discovery_cache/documents/bigtableadmin.v2.json
@@ -923,8 +923,47 @@
                     "https://www.googleapis.com/auth/cloud-platform.read-only"
                   ]
                 },
+                "partialUpdateCluster": {
+                  "description": "Partially updates a cluster within a project. This method is the preferred way to update a Cluster. ",
+                  "flatPath": "v2/projects/{projectsId}/instances/{instancesId}/clusters/{clustersId}",
+                  "httpMethod": "PATCH",
+                  "id": "bigtableadmin.projects.instances.clusters.partialUpdateCluster",
+                  "parameterOrder": [
+                    "name"
+                  ],
+                  "parameters": {
+                    "name": {
+                      "description": "The unique name of the cluster. Values are of the form `projects/{project}/instances/{instance}/clusters/a-z*`.",
+                      "location": "path",
+                      "pattern": "^projects/[^/]+/instances/[^/]+/clusters/[^/]+$",
+                      "required": true,
+                      "type": "string"
+                    },
+                    "updateMask": {
+                      "description": "Required. The subset of Cluster fields which should be replaced. Must be explicitly set.",
+                      "format": "google-fieldmask",
+                      "location": "query",
+                      "type": "string"
+                    }
+                  },
+                  "path": "v2/{+name}",
+                  "request": {
+                    "$ref": "Cluster"
+                  },
+                  "response": {
+                    "$ref": "Operation"
+                  },
+                  "scopes": [
+                    "https://www.googleapis.com/auth/bigtable.admin",
+                    "https://www.googleapis.com/auth/bigtable.admin.cluster",
+                    "https://www.googleapis.com/auth/bigtable.admin.instance",
+                    "https://www.googleapis.com/auth/cloud-bigtable.admin",
+                    "https://www.googleapis.com/auth/cloud-bigtable.admin.cluster",
+                    "https://www.googleapis.com/auth/cloud-platform"
+                  ]
+                },
                 "update": {
-                  "description": "Updates a cluster within an instance.",
+                  "description": "Updates a cluster within an instance. UpdateCluster is deprecated. Please use PartialUpdateCluster instead.",
                   "flatPath": "v2/projects/{projectsId}/instances/{instancesId}/clusters/{clustersId}",
                   "httpMethod": "PUT",
                   "id": "bigtableadmin.projects.instances.clusters.update",
@@ -1433,7 +1472,7 @@
                         "Only populates `name`.",
                         "Only populates `name` and fields related to the table's schema.",
                         "Only populates `name` and fields related to the table's replication state.",
-                        "Only populates 'name' and fields related to the table's encryption state.",
+                        "Only populates `name` and fields related to the table's encryption state.",
                         "Populates all fields."
                       ],
                       "location": "query",
@@ -1527,7 +1566,7 @@
                         "Only populates `name`.",
                         "Only populates `name` and fields related to the table's schema.",
                         "Only populates `name` and fields related to the table's replication state.",
-                        "Only populates 'name' and fields related to the table's encryption state.",
+                        "Only populates `name` and fields related to the table's encryption state.",
                         "Populates all fields."
                       ],
                       "location": "query",
@@ -1764,7 +1803,7 @@
       }
     }
   },
-  "revision": "20210326",
+  "revision": "20210405",
   "rootUrl": "https://bigtableadmin.googleapis.com/",
   "schemas": {
     "AppProfile": {