deps(major): update dependency phpunit/phpunit to v13 (#100)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

composer.json

@@ -31,7 +31,7 @@
     "guzzlehttp/psr7": "^1.7 || ^2.0"
   },
   "require-dev": {
-    "phpunit/phpunit": "^8.0 || ^9.0 || ^11.0 || ^12.0",
+    "phpunit/phpunit": "^8.0 || ^9.0 || ^11.0 || ^12.0 || ^13.0",
     "friendsofphp/php-cs-fixer": "^3.5"
   },
   "autoload": {