DEP Use PHPUnit 11

Author: emteknetnz

composer.json

@@ -8,7 +8,7 @@
         "silverstripe/cms": "^6"
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.6",
+        "phpunit/phpunit": "^11.3",
         "squizlabs/php_codesniffer": "^3",
         "silverstripe/standards": "^1",
         "phpstan/extension-installer": "^1.3"