Mark all non-internal Message classes final

Author: WyriHaximus

src/Message/Response.php

@@ -32,7 +32,7 @@
  *
  * @see \Psr\Http\Message\ResponseInterface
  */
-class Response extends Psr7Response
+final class Response extends Psr7Response
 {
     /**
      * @param int                                            $status  HTTP status code (e.g. 200/404)

src/Message/ResponseException.php

@@ -14,7 +14,7 @@
  * The `getCode(): int` method can be used to
  * return the HTTP response status code.
  */
-class ResponseException extends RuntimeException
+final class ResponseException extends RuntimeException
 {
     private $response;
 

src/Message/ServerRequest.php

@@ -29,7 +29,7 @@
  *
  * @see ServerRequestInterface
  */
-class ServerRequest extends Request implements ServerRequestInterface
+final class ServerRequest extends Request implements ServerRequestInterface
 {
     private $attributes = array();