Merge pull request #15 from vukhuu/fix-undefined-message-in-response

Fix undefined "message" in error response as there was only "errorDescription" in the response array instead

lib/Authsignal/AuthsignalClient.php

@@ -16,7 +16,7 @@ public static function apiUrl($url='')
   public function handleApiError($response, $status)
   {
     $type = $response['error'] ?? null;
-    $msg  = $response['message'];
+    $msg  = $response['errorDescription'] ?? null;
     switch ($status) {
       case 400:
         throw new AuthsignalBadRequest($msg, $type, $status);