Bump the astro group with 5 updates

Bumps the astro group with 5 updates:

| Package | From | To |
| --- | --- | --- |
| [@astrojs/preact](https://github.com/withastro/astro/tree/HEAD/packages/integrations/preact) | `4.1.3` | `5.1.0` |
| [@astrojs/rss](https://github.com/withastro/astro/tree/HEAD/packages/astro-rss) | `4.0.15` | `4.0.18` |
| [@astrojs/sitemap](https://github.com/withastro/astro/tree/HEAD/packages/integrations/sitemap) | `3.7.0` | `3.7.2` |
| [astro](https://github.com/withastro/astro/tree/HEAD/packages/astro) | `5.18.0` | `6.1.1` |
| [@astrojs/check](https://github.com/withastro/astro/tree/HEAD/packages/language-tools/astro-check) | `0.9.7` | `0.9.8` |


Updates `@astrojs/preact` from 4.1.3 to 5.1.0
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/main/packages/integrations/preact/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/@astrojs/preact@5.1.0/packages/integrations/preact)

Updates `@astrojs/rss` from 4.0.15 to 4.0.18
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/main/packages/astro-rss/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/@astrojs/rss@4.0.18/packages/astro-rss)

Updates `@astrojs/sitemap` from 3.7.0 to 3.7.2
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/main/packages/integrations/sitemap/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/@astrojs/sitemap@3.7.2/packages/integrations/sitemap)

Updates `astro` from 5.18.0 to 6.1.1
- [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@6.1.1/packages/astro)

Updates `@astrojs/check` from 0.9.7 to 0.9.8
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/main/packages/language-tools/astro-check/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/@astrojs/check@0.9.8/packages/language-tools/astro-check)

---
updated-dependencies:
- dependency-name: "@astrojs/preact"
  dependency-version: 5.1.0
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: astro
- dependency-name: "@astrojs/rss"
  dependency-version: 4.0.18
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: astro
- dependency-name: "@astrojs/sitemap"
  dependency-version: 3.7.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: astro
- dependency-name: astro
  dependency-version: 6.1.1
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: astro
- dependency-name: "@astrojs/check"
  dependency-version: 0.9.8
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: astro
...

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

Author: dependabot[bot]

package.json

@@ -19,17 +19,17 @@
     "redirects:generate": "node scripts/generate-gh-pages-redirects.mjs"
   },
   "dependencies": {
-    "@astrojs/preact": "^4.1.3",
-    "@astrojs/rss": "^4.0.15",
-    "@astrojs/sitemap": "^3.7.0",
+    "@astrojs/preact": "^5.1.0",
+    "@astrojs/rss": "^4.0.18",
+    "@astrojs/sitemap": "^3.7.2",
     "@fontsource-variable/fraunces": "^5.2.9",
     "@fontsource-variable/jetbrains-mono": "^5.2.8",
     "@fontsource-variable/plus-jakarta-sans": "^5.2.8",
     "@nanostores/preact": "^1.0.0",
     "@tailwindcss/vite": "^4.2.1",
     "@types/mdast": "^4.0.4",
     "@vercel/analytics": "^2.0.1",
-    "astro": "^5.18.0",
+    "astro": "^6.1.2",
     "nanostores": "^1.1.1",
     "preact": "^10.28.4",
     "shiki": "^4.0.1",
@@ -44,7 +44,7 @@
     ]
   },
   "devDependencies": {
-    "@astrojs/check": "^0.9.7",
+    "@astrojs/check": "^0.9.8",
     "@axe-core/playwright": "^4.11.1",
     "@playwright/test": "^1.58.2",
     "@resvg/resvg-js": "^2.6.2",