chore: update dependency knip to v6.21.0

Author: renovate[bot]

package.json

@@ -19,7 +19,7 @@
     "@inversifyjs/foundation-typescript-config": "0.2.0",
     "@inversifyjs/foundation-vitest-config": "0.2.0",
     "husky": "9.1.7",
-    "knip": "6.18.0",
+    "knip": "6.21.0",
     "lint-staged": "17.0.8",
     "turbo": "2.9.18"
   },