Bump @nuxtjs/sitemap from 2.4.0 to 5.1.0 (#1855)

Bumps [@nuxtjs/sitemap](https://github.com/nuxt-modules/sitemap) from 2.4.0 to 5.1.0.
- [Release notes](https://github.com/nuxt-modules/sitemap/releases)
- [Commits](nuxt-modules/sitemap@v2.4.0...v5.1.0)

---
updated-dependencies:
- dependency-name: "@nuxtjs/sitemap"
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>