Dropped the obsolete graphql_playground option from API Platform config (#187)

For more details see #187

Key changes:

* Dropped the obsolete `graphql_playground` option from API Platform config

* [Composer] Bumped api-platform/core to ~4.1.18

Author: alongosz

composer.json

@@ -28,7 +28,7 @@
         "ext-libxml": "*",
         "ext-simplexml": "*",
         "ext-xmlwriter": "*",
-        "api-platform/core": "~4.1.0",
+        "api-platform/core": "~4.1.18",
         "ibexa/core": "~5.0.x-dev",
         "ibexa/polyfill-php82": "^1.0",
         "ibexa/templated-uri-bundle": "^4.0",