chore(TestSetterAndGetter): Adhere to coding standard introduced with PR #3

Author: TiSiE

src/TestCase/TestSetterAndGetterTrait.php

@@ -1,4 +1,4 @@
-<?php declare(strict_types=1);
+<?php
 /**
  * CROSS PHPUnit Utils
  *
@@ -7,6 +7,8 @@
  * @copyright  2019 Cross Solution <http://cross-solution.de>
  */
 
+declare(strict_types=1);
+
 namespace Cross\TestUtils\TestCase;
 
 use Cross\TestUtils\Exception\InvalidUsageException;