docker/l3d#47 Composer 2 compatibility

composer.json

@@ -48,6 +48,7 @@
         "drupal/config_filter": "^2.0",
         "drupal/config_split": "^2.0",
         "drupal/core": "^9.0",
+        "drupal/core-composer-scaffold": "^9.0",
         "drupal/dev_modules": "^2.0",
         "drupal/drd_agent": "^4.0",
         "drupal/ds": "^3.7",