Bump vue from 3.4.20 to 3.4.21 in /frontend (#44)

Bumps [vue](https://github.com/vuejs/core) from 3.4.20 to 3.4.21.
- [Release notes](https://github.com/vuejs/core/releases)
- [Changelog](https://github.com/vuejs/core/blob/main/CHANGELOG.md)
- [Commits](vuejs/core@v3.4.20...v3.4.21)

---
updated-dependencies:
- dependency-name: vue
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

frontend/package-lock.json

@@ -13,7 +13,7 @@
   },
   "dependencies": {
     "axios": "^1.6.7",
-    "vue": "^3.4.20",
+    "vue": "^3.4.21",
     "vue-i18n": "^9.8.0"
   },
   "devDependencies": {