Upgrade: Bump hexo-generator-sitemap from 1.2.0 to 2.0.0

Bumps [hexo-generator-sitemap](https://github.com/hexojs/hexo-generator-sitemap) from 1.2.0 to 2.0.0.
- [Release notes](https://github.com/hexojs/hexo-generator-sitemap/releases)
- [Commits](https://github.com/hexojs/hexo-generator-sitemap/commits)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

package.json

@@ -46,7 +46,7 @@
     "hexo": "^4.0.0",
     "hexo-cli": "^3.0.0",
     "hexo-generator-index": "^1.0.0",
-    "hexo-generator-sitemap": "^1.2.0",
+    "hexo-generator-sitemap": "^2.0.0",
     "hexo-generator-tag": "^1.0.0",
     "hexo-renderer-handlebars": "^2.0.2",
     "hexo-server": "^1.0.0",