add support for phpunit 11 (#79)

* add support for phpunit 11

* moved phpunit requirement out of dev section

Author: wickedOne

composer.json

@@ -14,14 +14,9 @@
     ],
     "require": {
         "php": "^8.1",
+        "phpunit/phpunit": "^9.6 || ^10.0 || ^11.0",
         "symfony/config": "^5.4 || ^6.2 || ^7.0"
     },
-    "require-dev": {
-        "phpunit/phpunit": "^9.6 || ^10.0"
-    },
-    "conflict": {
-        "phpunit/phpunit": "<9.6 || >=11.0"
-    },
     "autoload": {
         "psr-4" : { "Matthias\\SymfonyConfigTest\\" : "" },
         "exclude-from-classmap": ["/Tests/"]