composer: update friendsofphp/php-cs-fixer requirement (#14)

Updates the requirements on [friendsofphp/php-cs-fixer](https://github.com/PHP-CS-Fixer/PHP-CS-Fixer) to permit the latest version.
- [Release notes](https://github.com/PHP-CS-Fixer/PHP-CS-Fixer/releases)
- [Changelog](https://github.com/PHP-CS-Fixer/PHP-CS-Fixer/blob/master/CHANGELOG.md)
- [Commits](PHP-CS-Fixer/PHP-CS-Fixer@v3.87.0...v3.88.2)

---
updated-dependencies:
- dependency-name: friendsofphp/php-cs-fixer
  dependency-version: 3.88.2
  dependency-type: direct:development
...

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

Author: dependabot[bot]

composer.json

@@ -27,7 +27,7 @@
     "require-dev": {
         "phpunit/phpunit": "*",
         "phpstan/phpstan": "*",
-        "friendsofphp/php-cs-fixer": "^3.87",
+        "friendsofphp/php-cs-fixer": "^3.88",
         "ergebnis/composer-normalize": "^2.48",
         "ergebnis/php-cs-fixer-config": "^6.55",
         "phpstan/phpstan-phpunit": "2.0.7"