Remove explicit dependency

Author: swissspidy

composer.json

@@ -20,7 +20,6 @@
         "phpstan/phpstan-deprecation-rules": "^1.2 || ^2.0",
         "phpstan/phpstan-phpunit": "^1.4 || ^2.0",
         "phpstan/phpstan-strict-rules": "^1.6 || ^2.0",
-        "sebastian/diff": "^4.0 || ^5.0 || ^6.0 || ^7.0",
         "swissspidy/phpstan-no-private": "^0.2.1 || ^1.0",
         "szepeviktor/phpstan-wordpress": "^v1.3.5",
         "wp-cli/config-command": "^1 || ^2",