build(deps): bump hexo from 4.2.0 to 5.1.1 in /site

Bumps [hexo](https://github.com/hexojs/hexo) from 4.2.0 to 5.1.1.
- [Release notes](https://github.com/hexojs/hexo/releases)
- [Commits](hexojs/hexo@4.2.0...5.1.1)

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

site/package.json

@@ -8,7 +8,7 @@
   },
   "dependencies": {
     "cheerio": "^0.22.0",
-    "hexo": "4.2.0",
+    "hexo": "5.1.1",
     "hexo-autoprefixer": "^2.0.0",
     "hexo-deployer-git": "^2.1.0",
     "hexo-generator-alias": "^0.1.3",