Bump eslint from 9.20.1 to 9.21.0 in /vue2/docs (#2260)

Bumps [eslint](https://github.com/eslint/eslint) from 9.20.1 to 9.21.0.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/main/CHANGELOG.md)
- [Commits](eslint/eslint@v9.20.1...v9.21.0)

---
updated-dependencies:
- dependency-name: eslint
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

vue2/docs/package.json

@@ -22,7 +22,7 @@
     "@vue/cli-plugin-router": "5.0.8",
     "@vue/cli-service": "5.0.8",
     "cpy-cli": "5.0.0",
-    "eslint": "9.20.1",
+    "eslint": "9.21.0",
     "eslint-plugin-vue": "9.32.0"
   }
 }