feat: add support for phpunit 13 (#20)

Author: W0rma

composer.json

@@ -23,7 +23,7 @@
 
     "require": {
         "php": "^8.2 || ^8.3 || ^8.4 || ^8.5",
-        "phpunit/phpunit": "^11.5 || ^12.0",
+        "phpunit/phpunit": "^11.5 || ^12.0 || ^13.0",
         "ext-dom": "*"
     },
     "autoload":{