Send data as body, not as query in RestRefundRequest::sendData

Author: Swahjak

src/Message/RestRefundRequest.php

@@ -67,6 +67,7 @@ public function sendData($data)
         $httpResponse = $this->sendRequest(
             'POST',
             '/orders/' . $data['id'] . '/refunds',
+            null,
             $data
         );