chore(deps): bump astro from 5.10.2 to 5.15.9

Bumps [astro](https://github.com/withastro/astro/tree/HEAD/packages/astro) from 5.10.2 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>

Author: dependabot[bot]

package.json

@@ -12,7 +12,7 @@
   "dependencies": {
     "@astrojs/starlight": "0.32.0",
     "@lunariajs/starlight": "0.1.1",
-    "astro": "^5.1.8",
+    "astro": "^5.15.9",
     "astro-matomo": "^1.7.0",
     "sharp": "^0.33.5",
     "starlight-cooler-credit": "^0.4.0"