feat: support fleet registration via cluster update

PiperOrigin-RevId: 529131876

google/container/v1/cluster_service.proto

@@ -2065,6 +2065,9 @@ message ClusterUpdate {
   // The desired node pool logging configuration defaults for the cluster.
   NodePoolLoggingConfig desired_node_pool_logging_config = 116;
 
+  // The desired fleet configuration for the cluster.
+  Fleet desired_fleet = 117;
+
   // The desired stack type of the cluster.
   // If a stack type is provided and does not match the current stack type of
   // the cluster, update will attempt to change the stack type to the new type.
@@ -2262,12 +2265,12 @@ message Operation {
   //
   // Examples:
   //
-  // -
-  // `https://container.googleapis.com/v1/projects/123/locations/us-central1/clusters/my-cluster`
-  // -
-  // `https://container.googleapis.com/v1/projects/123/zones/us-central1-c/clusters/my-cluster/nodePools/my-np`
-  // -
-  // `https://container.googleapis.com/v1/projects/123/zones/us-central1-c/clusters/my-cluster/nodePools/my-np/node/my-node`
+  //   -
+  //   `https://container.googleapis.com/v1/projects/123/locations/us-central1/clusters/my-cluster`
+  //   -
+  //   `https://container.googleapis.com/v1/projects/123/zones/us-central1-c/clusters/my-cluster/nodePools/my-np`
+  //   -
+  //   `https://container.googleapis.com/v1/projects/123/zones/us-central1-c/clusters/my-cluster/nodePools/my-np/node/my-node`
   string target_link = 7;
 
   // [Output only] The name of the Google Compute Engine