build(deps): bump @unhead/vue from 3.1.4 to 3.1.6 (#4367)

Bumps [@unhead/vue](https://github.com/unjs/unhead/tree/HEAD/packages/vue) from 3.1.4 to 3.1.6.
- [Release notes](https://github.com/unjs/unhead/releases)
- [Commits](https://github.com/unjs/unhead/commits/v3.1.6/packages/vue)

---
updated-dependencies:
- dependency-name: "@unhead/vue"
  dependency-version: 3.1.6
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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