update sponsor url

Author: yyx990803

themes/vue/_config.yml

@@ -18,7 +18,7 @@ platinum_sponsors_china:
     img: authing.svg
     height: 58
   - name: xitujuejin
-    url: https://juejin.cn/?utm_source=vue&utm_campaign=sponsor
+    url: https://juejin.cn/frontend?utm_source=vue&utm_campaign=sponsor
     img: xitu.png
     height: 54
 video_sponsors_china: