chore(deps-dev): bump eslint-config-next from 14.2.20 to 14.2.21 (#1304)

Bumps [eslint-config-next](https://github.com/vercel/next.js/tree/HEAD/packages/eslint-config-next) from 14.2.20 to 14.2.21.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](https://github.com/vercel/next.js/commits/v14.2.21/packages/eslint-config-next)

---
updated-dependencies:
- dependency-name: eslint-config-next
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

playground/next13-app-router/package.json

@@ -14,7 +14,7 @@
   },
   "devDependencies": {
     "eslint": "8.57.0",
-    "eslint-config-next": "14.2.20",
+    "eslint-config-next": "14.2.21",
     "next": "^13.4.2",
     "react": "^18.3.1",
     "react-dom": "^18.3.1",