Deprecate restore_policy in code

Author: rileykarson

google/resource_google_project_iam_policy.go

@@ -43,6 +43,7 @@ func resourceGoogleProjectIamPolicy() *schema.Resource {
 				Computed: true,
 			},
 			"restore_policy": &schema.Schema{
+				Deprecated: "This field will be removed alongside the authoritative field. To ignore changes not managed by Terraform, use google_project_iam_binding and google_project_iam_member instead. See https://www.terraform.io/docs/providers/google/r/google_project_iam.html for more information.",
 				Type:     schema.TypeString,
 				Computed: true,
 			},