Bump phpunit/phpunit from 8.5.8 to 9.4.2

Bumps [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit) from 8.5.8 to 9.4.2.
- [Release notes](https://github.com/sebastianbergmann/phpunit/releases)
- [Changelog](https://github.com/sebastianbergmann/phpunit/blob/master/ChangeLog-8.5.md)
- [Commits](https://github.com/sebastianbergmann/phpunit/compare/8.5.8...9.4.2)

Signed-off-by: dependabot[bot] <support@github.com>

composer.json

@@ -44,7 +44,7 @@
         "fzaninotto/faker": "^1.9.1",
         "mockery/mockery": "^1.0",
         "nunomaduro/collision": "^3.0",
-        "phpunit/phpunit": "^8.0",
+        "phpunit/phpunit": "^9.4",
         "symfony/thanks": "^1.0"
     },
     "autoload": {