MAGETWO-60034: Cannot ship remaining items in an order for several of one product if credit memo is made for some

- fix static test failure

Author: joanhe

dev/tests/functional/tests/app/Magento/Sales/Test/Constraint/AssertOrderCancelMassActionPartialFailMessage.php

@@ -3,6 +3,7 @@
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
+declare(strict_types=1);
 
 namespace Magento\Sales\Test\Constraint;