Update phpunit/phpunit requirement from ^9.0 to ^11.3 (#280)

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/main/ChangeLog-11.3.md)
- [Commits](sebastianbergmann/phpunit@9.0.0...11.3.0)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

composer.json

@@ -29,7 +29,7 @@
   },
   "require-dev": {
     "mockery/mockery": "^1.3",
-    "phpunit/phpunit": "^9.0",
+    "phpunit/phpunit": "^11.3",
     "jetbrains/phpstorm-attributes": "^1.0",
     "phpstan/phpstan": "^1.7",
     "laravel/pint": "^1.2"