Update composer dependencies

vendor/symfony/event-dispatcher/Tests/ChildEventDispatcherTest.php

@@ -0,0 +1,26 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\EventDispatcher\Tests;
+
+use Symfony\Component\EventDispatcher\EventDispatcher;
+
+class ChildEventDispatcherTest extends EventDispatcherTest
+{
+    protected function createEventDispatcher()
+    {
+        return new ChildEventDispatcher();
+    }
+}
+
+class ChildEventDispatcher extends EventDispatcher
+{
+}