fix(route): pixiv ranking tags (#13803)

lib/v2/pixiv/ranking.js

@@ -86,6 +86,7 @@ module.exports = async (ctx) => {
                 description: `<p>画师：${illust.user.name} - 阅览数：${illust.total_view} - 收藏数：${illust.total_bookmarks}</p><br>${images.join('')}`,
                 link: `https://www.pixiv.net/artworks/${illust.id}`,
                 author: illust.user.name,
+                category: illust.tags.map((tag) => tag.name),
             };
         }),
     };