Raising requirements for PHPUnit to 9.5.28

Author: Hackwar

composer.json

@@ -12,7 +12,7 @@
     "require-dev": {
         "doctrine/inflector": "^1.2",
         "joomla/test": "3.0.x-dev",
-        "phpunit/phpunit": "^9.0",
+        "phpunit/phpunit": "^9.5.28",
         "squizlabs/php_codesniffer": "~3.7.1"
     },
     "conflict": {