Backout PHPUnit 11 support to fix CI

Author: TRowbotham

composer.json

@@ -22,7 +22,7 @@
         "phpstan/phpstan": "^1.9",
         "phpstan/phpstan-deprecation-rules": "^1.0",
         "phpstan/phpstan-strict-rules": "^1.0",
-        "phpunit/phpunit": "^10.0 || ^11.0",
+        "phpunit/phpunit": "^10.0",
         "slevomat/coding-standard": "^8.0",
         "squizlabs/php_codesniffer": "^3.7.1",
         "symfony/cache": "^5.0 || ^6.0"