chore(deps): bump astro

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


Updates `astro` from 5.18.1 to 6.1.6
- [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@6.1.6/packages/astro)

---
updated-dependencies:
- dependency-name: astro
  dependency-version: 6.1.6
  dependency-type: direct:production
  dependency-group: npm_and_yarn
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]