Allow Symfony 6

Author: derrabus

composer.json

@@ -26,7 +26,7 @@
         "symfony/http-kernel": ""
     },
     "require-dev": {
-        "symfony/http-kernel": "^5.3"
+        "symfony/http-kernel": "^5.3|^6.0"
     },
     "conflict": {
         "symfony/http-kernel": "<5.3"