chore(deps): update devdependency eslint to ^9.21.0

Author: renovate[bot]

package.json

@@ -38,7 +38,7 @@
     "@types/node": "^22.13.5",
     "@vitest/coverage-v8": "^3.0.6",
     "changelogen": "^0.5.7",
-    "eslint": "^9.20.1",
+    "eslint": "^9.21.0",
     "typescript": "^5.7.3",
     "unbuild": "^3.3.1",
     "vite": "^6.1.1",