Merge pull request #76 from oliverklee/task/phpunit-downgrade

[TASK] Downgrade to PHPUnit 8.5

Author: sascha-egerer

composer.json

@@ -19,7 +19,7 @@
         "php-parallel-lint/php-parallel-lint": "^1.3",
         "phing/phing": "^2.17",
         "phpstan/phpstan-strict-rules": "^1.0",
-        "phpunit/phpunit": "^9.5",
+        "phpunit/phpunit": "^8.5.30",
         "symfony/polyfill-php80": "^1.26.0"
     },
     "autoload": {