chore(landing)(deps): Bump the astro group across 1 directory with 3 updates

Bumps the astro group with 3 updates in the /landing directory: [@astrojs/rss](https://github.com/withastro/astro/tree/HEAD/packages/astro-rss), [@astrojs/sitemap](https://github.com/withastro/astro/tree/HEAD/packages/integrations/sitemap) and [astro](https://github.com/withastro/astro/tree/HEAD/packages/astro).


Updates `@astrojs/rss` from 4.0.18 to 4.0.19
- [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@4.0.19/packages/astro-rss)

Updates `@astrojs/sitemap` from 3.7.2 to 3.7.3
- [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@3.7.3/packages/integrations/sitemap)

Updates `astro` from 5.18.1 to 5.18.2
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/astro@5.18.2/packages/astro/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/astro@5.18.2/packages/astro)

---
updated-dependencies:
- dependency-name: "@astrojs/rss"
  dependency-version: 4.0.19
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: astro
- dependency-name: "@astrojs/sitemap"
  dependency-version: 3.7.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: astro
- dependency-name: astro
  dependency-version: 5.18.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: astro
...

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

Author: dependabot[bot]

landing/package-lock.json

@@ -15,10 +15,10 @@
     "test:i18n": "node scripts/check-i18n.mjs"
   },
   "dependencies": {
-    "@astrojs/rss": "^4.0.18",
-    "@astrojs/sitemap": "^3.2.1",
+    "@astrojs/rss": "^4.0.19",
+    "@astrojs/sitemap": "^3.7.3",
     "@tailwindcss/vite": "^4.0.0",
-    "astro": "^5.1.0",
+    "astro": "^5.18.2",
     "tailwindcss": "^4.0.0"
   },
   "devDependencies": {