Bump astro from 5.15.2 to 5.15.6

Bumps [astro](https://github.com/withastro/astro/tree/HEAD/packages/astro) from 5.15.2 to 5.15.6.
- [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@5.15.6/packages/astro)

---
updated-dependencies:
- dependency-name: astro
  dependency-version: 5.15.6
  dependency-type: direct:development
...

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

Author: dependabot[bot]

package-lock.json

@@ -13,7 +13,7 @@
   },
   "devDependencies": {
     "@astrojs/check": "^0.9.4",
-    "astro": "^5.11.0",
+    "astro": "^5.15.6",
     "astro-compress": "^2.3.8",
     "sharp": "^0.34.3",
     "typescript": "^5.8.3"