adds code of conduct link to sidebar menu

Author: daffodil11

_includes/sidebar.html

@@ -57,6 +57,12 @@
                         <span>Contact</span>
                     </a>
                 </li>
+                <li class="sidebar-dropdown">
+                    <a href="{{site.url}}/code-of-conduct">
+                        <i class="fas fa-book"></i>
+                        <span>Code of Conduct</span>
+                    </a>
+                </li>
                 <li class="sidebar-dropdown">
                     <a href="{{site.url}}/feedback">
                         <i class="fa fa-comment-alt"></i>