removed unused use statement

Author: tobias-trozowski

test/ResourceGenerator/ResourceWithSelfReferringInstanceTest.php

@@ -10,7 +10,6 @@
 use PHPUnit\Framework\TestCase;
 use Psr\Container\ContainerInterface;
 use Psr\Http\Message\ServerRequestInterface;
-use function var_dump;
 use Zend\Expressive\Hal\HalResource;
 use Zend\Expressive\Hal\Link;
 use Zend\Expressive\Hal\LinkGenerator;