deps(website): bump astro

Bumps the astro group with 1 update in the /website directory: [astro](https://github.com/withastro/astro/tree/HEAD/packages/astro).


Updates `astro` from 5.18.2 to 6.4.4
- [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/astro@6.4.4/packages/astro)

---
updated-dependencies:
- dependency-name: astro
  dependency-version: 6.4.4
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: astro
...

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Author: dependabot[bot]