Add link to news.vuejs.org to ecosystem dropdown (#1478)

Author: shentao

themes/vue/layout/partials/ecosystem_dropdown.ejs

@@ -22,6 +22,7 @@
     </ul></li>
     <li><h4>News</h4></li>
     <li><ul>
+      <li><a href="https://news.vuejs.org" class="nav-link" target="_blank">Weekly News</a></li>
       <li><a href="https://github.com/vuejs/roadmap" class="nav-link" target="_blank">Roadmap</a></li>
       <li><a href="https://twitter.com/vuejs" class="nav-link" target="_blank">Twitter</a></li>
       <li><a href="https://medium.com/the-vue-point" class="nav-link" target="_blank">Blog</a></li>