Bump astro in /docs in the npm_and_yarn group across 1 directory (#56)

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


Updates `astro` from 5.18.1 to 6.1.8
- [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@6.1.8/packages/astro)

---
updated-dependencies:
- dependency-name: astro
  dependency-version: 6.1.8
  dependency-type: direct:production
  dependency-group: npm_and_yarn
...

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Author: dependabot[bot]