Fix namespace

lib/SimpleSAML/Error/AuthSource.php

@@ -30,7 +30,7 @@ class AuthSource extends Error
      *
      * @param string $authsource  Authsource module name from where this error was thrown.
      * @param string $reason  Description of the error.
-     * @param Exception|null $cause
+     * @param \Exception|null $cause
      */
     public function __construct($authsource, $reason, $cause = null)
     {