DNS policy module fixes (#1278)

* dns response policy module

* tfdoc

* Add dns policy tests

* fix copyright, var description, initial wording

---------

Co-authored-by: Julio Castillo <jccb@google.com>

modules/dns-response-policy/variables.tf

@@ -1,5 +1,5 @@
 /**
- * Copyright 2022 Google LLC
+ * Copyright 2023 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -28,7 +28,7 @@ variable "description" {
 }
 
 variable "name" {
-  description = "Zone name, must be unique within the project."
+  description = "Policy name."
   type        = string
 }