Update Composer, update everything

vendor/symfony/dependency-injection/Tests/Fixtures/containers/CustomContainer.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace Symfony\Component\DependencyInjection\Tests\Fixtures\containers;
+
+use Symfony\Component\DependencyInjection\Container;
+use Symfony\Component\DependencyInjection\ParameterBag\ParameterBag;
+
+class CustomContainer extends Container
+{
+    public function getBarService()
+    {
+    }
+
+    public function getFoobarService()
+    {
+    }
+}