Apply php-cs-fixer rule for array_key_exists()

Author: nicolas-grekas

DependencyInjection/SecurityExtension.php

@@ -479,7 +479,7 @@ private function createFirewall(ContainerBuilder $container, $id, $firewall, &$a
         foreach ($this->factories as $position) {
             foreach ($position as $factory) {
                 $key = str_replace('-', '_', $factory->getKey());
-                if (array_key_exists($key, $firewall)) {
+                if (\array_key_exists($key, $firewall)) {
                     $listenerKeys[] = $key;
                 }
             }