chore(deps): add @astrojs/sitemap

Author: KuangPF

package.json

@@ -12,6 +12,7 @@
   "dependencies": {
     "@astrojs/mdx": "1.1.0",
     "@astrojs/react": "3.0.2",
+    "@astrojs/sitemap": "^3.0.1",
     "@docsearch/css": "^3.5.2",
     "@docsearch/js": "^3.5.2",
     "@types/mdast": "^3.0.11",