Update phpunit/phpunit requirement from ^9.5.19 to ^9.5.19 || ^12.0.0

Updates the requirements on [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit) to permit the latest version.
- [Release notes](https://github.com/sebastianbergmann/phpunit/releases)
- [Changelog](https://github.com/sebastianbergmann/phpunit/blob/12.3.0/ChangeLog-12.3.md)
- [Commits](sebastianbergmann/phpunit@9.5.19...12.3.0)

---
updated-dependencies:
- dependency-name: phpunit/phpunit
  dependency-version: 12.3.0
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

composer.json

@@ -48,7 +48,7 @@
         "ext-pdo": "*",
         "cakephp/cakephp-codesniffer": "^5.0",
         "cakephp/i18n": "^5.0",
-        "phpunit/phpunit": "^9.5.19",
+        "phpunit/phpunit": "^9.5.19 || ^12.0.0",
         "symfony/yaml": "^4.0|^5.0|^6.0|^7.0"
     },
     "autoload": {