Add GitHub logo (#51)

Author: sy-records

themes/OpenSouceWin/layout/index.ejs

@@ -58,6 +58,11 @@
             <%- image_tag('img/logo-xlab.png', {class: 'icons mb-3', alt: 'x-lab'}) %>
         </div>
 
+        <div class="subtitle mt-4">官方支持</div>
+        <div class="icons-wrap">
+            <a href="https://github.com" title="GitHub" target="_blank"><%- image_tag('img/logo-octocat.png', {class: 'icons mb-3', alt: 'GitHub'}) %></a>
+        </div>
+
         <div class="subtitle mt-4">合作社区</div>
         <div class="icons-wrap">
             <%- image_tag('img/logo-kyuubi.png', {class: 'icons2 m-2', alt: 'Kyuubi'}) %>