Update GitHub logo (#52)

Author: sy-records

themes/OpenSouceWin/layout/index.ejs

@@ -60,7 +60,7 @@
 
         <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>
+            <a href="https://github.com" title="GitHub" target="_blank"><%- image_tag('img/logo-github.png', {class: 'icons mb-3', alt: 'GitHub'}) %></a>
         </div>
 
         <div class="subtitle mt-4">合作社区</div>