build: add support for the older phpunit 8.5 to allow usage on php 7.2

Author: yCodeTech

composer.json

@@ -22,7 +22,7 @@
         "dealerdirect/phpcodesniffer-composer-installer": "^1.1"
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.6||^11.5",
+        "phpunit/phpunit": "^8.5||^9.6||^11.5",
         "phpcsstandards/phpcsdevtools": "^1.0",
         "php-parallel-lint/php-parallel-lint": "^1.4"
     },