Add samples for dual-stack and ipv6-only subnet creation (#891)

* Prepared network_ipv6 for inclusion in C.G.C. documentation

* ci: skip tests for complex sample

* use standard naming for singleton resource

* correct region tags

* new samples get current date

---------

Co-authored-by: Katie McLaughlin <[email protected]>

Author: jarzynskila

vpc/network_ipv6/main.tf

@@ -0,0 +1,44 @@
+/**
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+# [START vpc_ipv6_internal]
+resource "google_compute_network" "default" {
+  name                     = "vpc-network-ipv6"
+  auto_create_subnetworks  = false
+  enable_ula_internal_ipv6 = true
+}
+# [END vpc_ipv6_internal]
+
+# [START vpc_subnet_dual_stack]
+resource "google_compute_subnetwork" "subnet_dual_stack" {
+  name             = "subnet-dual-stack"
+  ip_cidr_range    = "10.0.0.0/22"
+  region           = "us-west2"
+  stack_type       = "IPV4_IPV6"
+  ipv6_access_type = "INTERNAL"
+  network          = google_compute_network.default.id
+}
+# [END vpc_subnet_dual_stack]
+
+# [START vpc_subnet_ipv6_only]
+resource "google_compute_subnetwork" "subnet_ipv6_only" {
+  name             = "subnet-ipv6-only"
+  region           = "us-central1"
+  network          = google_compute_network.default.id
+  stack_type       = "IPV6_ONLY"
+  ipv6_access_type = "INTERNAL"
+}
+# [END vpc_subnet_ipv6_only]

vpc/network_ipv6/test.yaml

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+# Copyright 2022 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+apiVersion: blueprints.cloud.google.com/v1alpha1
+kind: BlueprintTest
+metadata:
+  name: vpc_network_ipv6
+spec:
+  skip: true