feat(route): add Luogu user blog (#11527)

* feat(route): add Luogu user blog

* used html as description instead

* Do not set pubDate if there isn't any.

* used Luogu API

lib/v2/luogu/router.js

@@ -2,4 +2,5 @@ module.exports = (router) => {
     router.get('/contest', require('./contest'));
     router.get('/daily/:id?', require('./daily'));
     router.get('/user/feed/:uid', require('./userFeed'));
+    router.get('/user/blog/:username', require('./userBlog'));
 };