chore(deps): bump astro from 5.15.6 to 5.15.9 (#1006)

Bumps [astro](https://github.com/withastro/astro/tree/HEAD/packages/astro) from 5.15.6 to 5.15.9.
- [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@5.15.9/packages/astro)

---
updated-dependencies:
- dependency-name: astro
  dependency-version: 5.15.9
  dependency-type: direct:production
...

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

Author: dependabot[bot]

package-lock.json

@@ -16,7 +16,7 @@
   "dependencies": {
     "@astrojs/sitemap": "^3.6.0",
     "@astrojs/starlight": "^0.36.2",
-    "astro": "^5.15.6",
+    "astro": "^5.15.9",
     "sharp": "^0.34.5"
   },
   "devDependencies": {