Remove ForceNew attribute from external_ipv6

Author: victorsantos-cit

mmv1/third_party/terraform/services/compute/resource_compute_instance.go.tmpl

@@ -752,7 +752,6 @@ func ResourceComputeInstance() *schema.Resource {
 										Type:             schema.TypeString,
 										Optional:         true,
 										Computed:         true,
-										ForceNew:         false,
 										DiffSuppressFunc: ipv6RepresentationDiffSuppress,
 										Description:      `The first IPv6 address of the external IPv6 range associated with this instance, prefix length is stored in externalIpv6PrefixLength in ipv6AccessConfig. To use a static external IP address, it must be unused and in the same region as the instance's zone. If not specified, Google Cloud will automatically assign an external IPv6 address from the instance's subnetwork.`,
 									},