Update navbar.html

Author: wobrschalek

_includes/navbar.html

@@ -17,6 +17,7 @@
             <a class="dropdown-item" href="about.html">About Us</a>
             <a class="dropdown-item" href="impacts.html">Impacts</a>
             <a class="dropdown-item" href="https://github.com/Open-MBEE/open-mbee.github.io/wiki/Publications">Publications</a>
+            <a class="dropdown-item" href="https://github.com/Open-MBEE/open-mbee.github.io/wiki/OpenMBEE-Sponsors">Sponsors</a>
           </div>
         </li>
         <li class="nav-item"><a class="nav-link" href="numfocus.html" role="button">NumFOCUS Project</a></li>