fix: use version 15.0 of bootstrap-package

Author: maikschneider

composer.json

@@ -18,7 +18,7 @@
     "roave/security-advisories": "dev-latest",
     "typo3/cms-base-distribution": "^12.0",
     "typo3/cms-lowlevel": "^12.0",
-    "bk2k/bootstrap-package": "dev-master",
+    "bk2k/bootstrap-package": "^15.0",
     "friendsofphp/php-cs-fixer": "^3.12",
     "saschaegerer/phpstan-typo3": "^1.9",
     "helhum/typo3-console": "^8.0",