Bump phpunit/phpunit in /sourcecode/apis/contentauthor

Bumps [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit) from 9.5.28 to 10.3.5.
- [Changelog](https://github.com/sebastianbergmann/phpunit/blob/10.3.5/ChangeLog-10.3.md)
- [Commits](sebastianbergmann/phpunit@9.5.28...10.3.5)

---
updated-dependencies:
- dependency-name: phpunit/phpunit
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

sourcecode/apis/contentauthor/composer.json

@@ -53,7 +53,7 @@
         "mockery/mockery": "^1.0",
         "nunomaduro/larastan": "^2.0",
         "phpstan/phpstan": "^1.7",
-        "phpunit/phpunit": "^9.5",
+        "phpunit/phpunit": "^10.3",
         "symfony/css-selector": "^4.0"
     },
     "autoload": {