Merge branch '9.18' into 9.19

Author: GrahamCampbell

lib/Gitlab/HttpClient/Message/ResponseMediator.php

@@ -76,10 +76,6 @@ public static function getPagination(ResponseInterface $response)
      */
     private static function getHeader(ResponseInterface $response, $name)
     {
-        if (!$response->hasHeader('Link')) {
-            return null;
-        }
-
         $headers = $response->getHeader($name);
 
         return array_shift($headers);