Bump @eslint/js from 9.20.0 to 9.21.0

Bumps [@eslint/js](https://github.com/eslint/eslint/tree/HEAD/packages/js) from 9.20.0 to 9.21.0.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/main/CHANGELOG.md)
- [Commits](https://github.com/eslint/eslint/commits/v9.21.0/packages/js)

---
updated-dependencies:
- dependency-name: "@eslint/js"
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -45,7 +45,7 @@
   },
   "devDependencies": {
     "@antfu/eslint-config": "4.3.0",
-    "@eslint/js": "^9.20.0",
+    "@eslint/js": "^9.21.0",
     "@types/node": "^22.13.4",
     "eslint": "^9.20.1",
     "globals": "^15.15.0",