Update dependency phpunit/phpunit to v12 (#591)

* Update phpunit/phpunit requirement from ^11.3.6 to ^11.3.6 || ^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/12.0.2/ChangeLog-12.0.md)
- [Commits](sebastianbergmann/phpunit@11.3.6...12.0.2)

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

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

* Update composer.json

---------

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

composer.json

@@ -35,7 +35,7 @@
         "phpstan/phpstan": "^1.12.4",
         "phpstan/phpstan-phpunit": "^1.4.0",
         "phpstan/phpstan-strict-rules": "^1.6.1",
-        "phpunit/phpunit": "^11.3.6"
+        "phpunit/phpunit": "^12.0.2"
     },
     "autoload": {
         "psr-4": {