Bump php-actions/phpunit from 3 to 7

Bumps [php-actions/phpunit](https://github.com/php-actions/phpunit) from 3 to 7.
- [Release notes](https://github.com/php-actions/phpunit/releases)
- [Commits](php-actions/phpunit@v3...v7)

---
updated-dependencies:
- dependency-name: php-actions/phpunit
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/ci.yml

@@ -35,7 +35,7 @@ jobs:
           php_version: ${{ matrix.php }}
 
       - name: PHPUnit Tests
-        uses: php-actions/phpunit@v3
+        uses: php-actions/phpunit@v7
         with:
           version: ${{ matrix.phpunit }}
           php_version: ${{ matrix.php }}