Support IPV6 for HA VPN. (GoogleCloudPlatform#7525)

mmv1/products/compute/VpnGateway.yaml

@@ -52,6 +52,12 @@ examples:
     vars:
       ha_vpn_gateway1_name: "ha-vpn-1"
       network1_name: "network1"
+  - !ruby/object:Provider::Terraform::Examples
+    name: "ha_vpn_gateway_ipv6"
+    primary_resource_id: "ha_gateway1"
+    vars:
+      ha_vpn_gateway1_name: "ha-vpn-1"
+      network1_name: "network1"
   - !ruby/object:Provider::Terraform::Examples
     name: "ha_vpn_gateway_gcp_to_gcp"
     primary_resource_id: "ha_gateway1"
@@ -126,6 +132,16 @@ properties:
       The network this VPN gateway is accepting traffic for.
     required: true
     immutable: true
+  - !ruby/object:Api::Type::Enum
+    name: 'stackType'
+    description: |
+      The stack type for this VPN gateway to identify the IP protocols that are enbaled.
+      If not specified, IPV4_ONLY will be used.
+    default_value: :IPV4_ONLY
+    values:
+      - :IPV4_ONLY
+      - :IPV4_IPV6
+    immutable: true  
   - !ruby/object:Api::Type::Array
     name: 'vpnInterfaces'
     description: |

mmv1/templates/terraform/examples/ha_vpn_gateway_ipv6.tf.erb

@@ -0,0 +1,11 @@
+resource "google_compute_ha_vpn_gateway" "ha_gateway1" {
+  region   = "us-central1"
+  name     = "<%= ctx[:vars]['ha_vpn_gateway1_name'] %>"
+  network  = google_compute_network.network1.id
+  stack_type = "IPV4_IPV6"
+}
+
+resource "google_compute_network" "network1" {
+  name                    = "<%= ctx[:vars]['network1_name'] %>"
+  auto_create_subnetworks = false
+}