Add comma to array last element to fix php fixer

Author: GCalmels

DependencyInjection/AsyncTransformersPass.php

@@ -33,7 +33,7 @@ public function process(ContainerBuilder $container)
                     $defaultTransformer = [
                         'id' => $serviceId,
                         'transformerName' => $transformerName,
-                        'eventName' => $eventName
+                        'eventName' => $eventName,
                     ];
                 } else {
                     $eventNamesMap[$eventName] = $transformerName;