chore(deps): bump the npm group with 3 updates (#1090)

Bumps the npm group with 3 updates: [@astrojs/sitemap](https://github.com/withastro/astro/tree/HEAD/packages/integrations/sitemap), [@astrojs/starlight](https://github.com/withastro/starlight/tree/HEAD/packages/starlight) and [astro](https://github.com/withastro/astro/tree/HEAD/packages/astro).


Updates `@astrojs/sitemap` from 3.7.0 to 3.7.1
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/main/packages/integrations/sitemap/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/@astrojs/[email protected]/packages/integrations/sitemap)

Updates `@astrojs/starlight` from 0.37.7 to 0.38.1
- [Release notes](https://github.com/withastro/starlight/releases)
- [Changelog](https://github.com/withastro/starlight/blob/main/packages/starlight/CHANGELOG.md)
- [Commits](https://github.com/withastro/starlight/commits/@astrojs/[email protected]/packages/starlight)

Updates `astro` from 5.18.0 to 6.0.4
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/main/packages/astro/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/[email protected]/packages/astro)

---
updated-dependencies:
- dependency-name: "@astrojs/sitemap"
  dependency-version: 3.7.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: npm
- dependency-name: "@astrojs/starlight"
  dependency-version: 0.38.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: npm
- dependency-name: astro
  dependency-version: 6.0.4
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: npm
...

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

Author: dependabot[bot]