fixed DocBlock in 'addComment' method

Author: alfredbez

lib/Gitlab/Api/MergeRequests.php

@@ -179,7 +179,7 @@ public function showComments($project_id, $mr_id)
     /**
      * @param int $project_id
      * @param int $mr_id
-     * @param int $note
+     * @param string $note
      * @return mixed
      */
     public function addComment($project_id, $mr_id, $note)