fix(deps): make it compatible with PHPUnit >= 12

Author: tchapuis

composer.json

@@ -10,7 +10,7 @@
         "php": ">=8.2",
         "nette/utils": "^4.0.5",
         "phar-io/version": "^3.2",
-        "sebastian/diff": "^6.0",
+        "sebastian/diff": "^6.0 || ^7.0",
         "symfony/config": "^7.0",
         "symfony/console": "^7.0",
         "symfony/dependency-injection": "^7.0",