📦 Downgrade phpunit for PHP 8.1 support

Author: andrew-demb

composer.json

@@ -22,7 +22,7 @@
     "symfony/validator": "^6.4 || ^7.0 || ^8.0"
   },
   "require-dev": {
-    "phpunit/phpunit": "^11",
+    "phpunit/phpunit": "^10",
     "mouf/picotainer": "^1.1",
     "phpstan/phpstan": "^2",
     "php-coveralls/php-coveralls": "^2.1.0",