Update PHPUnit version requirement to ^13.0

Author: ADmad

composer.json

@@ -35,7 +35,7 @@
     },
     "require-dev": {
         "cakephp/cakephp-codesniffer": "^6.0",
-        "phpunit/phpunit": "^12.1.3 || ^13.0"
+        "phpunit/phpunit": "^13.0"
     },
     "suggest": {
         "ext-pdo_sqlite": "DebugKit needs to store panel data in a database. SQLite is simple and easy to use."