feat: Add support for specifying stack type for clusters. This will a…

…llow clusters to be created as dual stack or toggled between IPV4 and dual stack (#3781)

- [ ] Regenerate this pull request now.

Clients can now configure dual stack clusters by specifying a stack type of IPV4_IPV6 during cluster creation, or with an update command. When used with a cluster creation command that creates a new subnet, the ipv6_access_type field can be used to specify whether the subnet has internal or external IPv6 access. When used with a cluster update command, the subnet must already be dual stack.

PiperOrigin-RevId: 495981345

Source-Link: https://togithub.com/googleapis/googleapis/commit/9d1290ea4d6d14434b9321277edfde4a9616695c

Source-Link: https://togithub.com/googleapis/googleapis-gen/commit/31ed74bbd1990351a87bda1a4570ba08374281b7
Copy-Tag: eyJwIjoicGFja2FnZXMvZ29vZ2xlLWNvbnRhaW5lci8uT3dsQm90LnlhbWwiLCJoIjoiMzFlZDc0YmJkMTk5MDM1MWE4N2JkYTFhNDU3MGJhMDgzNzQyODFiNyJ9

packages/google-container/protos/google/container/v1beta1/cluster_service.proto

@@ -2179,6 +2179,11 @@ message ClusterUpdate {
 
   // The desired node pool logging configuration defaults for the cluster.
   NodePoolLoggingConfig desired_node_pool_logging_config = 116;
+
+  // 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.
+  StackType desired_stack_type = 119;
 }
 
 // This operation resource represents operations that may have happened or are
@@ -5213,3 +5218,15 @@ enum DatapathProvider {
   // for more.
   ADVANCED_DATAPATH = 2;
 }
+
+// Possible values for IP stack type
+enum StackType {
+  // By default, the clusters will be IPV4 only
+  STACK_TYPE_UNSPECIFIED = 0;
+
+  // The value used if the cluster is a IPV4 only
+  IPV4 = 1;
+
+  // The value used if the cluster is a dual stack cluster
+  IPV4_IPV6 = 2;
+}