Add GitHub link

Author: tcbegley

docs/templates/macros/navbar.html

@@ -64,6 +64,14 @@
         </li>
       </ul>
       <ul class="navbar-nav flex-row flex-wrap ms-auto" >
+        <li>
+          <li class="nav-item">
+            <a href="https://github.com/facultyai/dash-bootstrap-components" class="nav-link">
+              <i class="bi bi-github ms-1"></i>
+              <span class="d-lg-none ms-2">Source code</span>
+            </a>
+          </li>
+        </li>
         {% if dark_mode_toggle %}
         <li class="nav-item dropdown">
           <button