feat: update dingding group

Author: wangxueliang

ding.jpeg

@@ -82,7 +82,11 @@ export default {
               <a-menu-item key='sponsor'>
                 <a-popover placement='bottom'>
                   <template slot='content'>
-                    <img/>
+                    <img
+                      width='160'
+                      alt='dingding'
+                      src='https://user-images.githubusercontent.com/4122593/50038786-571eaf80-0060-11e9-98a1-ea202fc60859.png'
+                    />
                   </template>
                   <a-icon type='dingding' />
                   {isCN ? '钉钉服务群' : 'Ding Group QR Code'}