feat: fix deprecation for Extension

DependencyInjection/DukecityCommandSchedulerExtension.php

@@ -5,7 +5,7 @@
 use Symfony\Component\Config\FileLocator;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Loader\PhpFileLoader;
-use Symfony\Component\HttpKernel\DependencyInjection\Extension;
+use Symfony\Component\DependencyInjection\Extension\Extension;
 
 /**
  * This is the class that loads and manages your bundle configuration