Update phpunit/phpunit requirement from ^9.1 to ^11.3

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/11.3.0/ChangeLog-11.3.md)
- [Commits](sebastianbergmann/phpunit@9.1.0...11.3.0)

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

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

composer.json

@@ -18,7 +18,7 @@
     "require-dev": {
         "fakerphp/faker": "^1.9",
         "mikey179/vfsstream": "^1.6",
-        "phpunit/phpunit": "^9.1"
+        "phpunit/phpunit": "^11.3"
     },
     "autoload": {
         "exclude-from-classmap": [