Update MockHttpResponse.php

Author: inhere

src/websocket-server/test/testing/MockHttpResponse.php

@@ -92,7 +92,8 @@ public function cookie(
         $domain = null,
         $secure = null,
         $httpOnly = null,
-        $samesite = null
+        $samesite = null,
+        $priority = null
     ) {
         $result = \urlencode($name) . '=' . \urlencode($value);