Update dependency phpunit/phpunit to v13 [SECURITY]

Author: renovate[bot]

composer.json

@@ -23,7 +23,7 @@
         "ext-mbstring": "*"
     },
     "require-dev": {
-        "phpunit/phpunit": "~4.8",
+        "phpunit/phpunit": "~13.0",
         "satooshi/php-coveralls": "~1.0",
         "squizlabs/php_codesniffer": "~2.6",
         "friendsofphp/php-cs-fixer": "~1.12"