build(deps-dev): bump @astrojs/sitemap from 3.0.4 to 3.1.6

Bumps [@astrojs/sitemap](https://github.com/withastro/astro/tree/HEAD/packages/integrations/sitemap) from 3.0.4 to 3.1.6.
- [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@3.1.6/packages/integrations/sitemap)

---
updated-dependencies:
- dependency-name: "@astrojs/sitemap"
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

package.json

@@ -40,7 +40,7 @@
 	},
 	"devDependencies": {
 		"@astrojs/mdx": "2.3.1",
-		"@astrojs/sitemap": "3.0.4",
+		"@astrojs/sitemap": "3.1.6",
 		"@astrojs/tailwind": "5.1.0",
 		"@pagefind/default-ui": "^1.0.4",
 		"@tailwindcss/typography": "0.5.10",