added projects link

Author: manfred-kaiser

_includes/header_links.html

@@ -1,6 +1,9 @@
 <li class="nav-item mr-lg-4">
     <a class="nav-link" href="https://docs.ssh-mitm.at">Docs<i class="fas fa-book ml-2"></i></a>
 </li>
+<li class="nav-item mr-lg-4">
+    <a class="nav-link" href="https://www.ssh-mitm.at/projects.html">Projects<i class="fas fa-tasks ml-2"></i></a>
+</li>
 <li class="nav-item mr-lg-4">
     <a class="nav-link" href="https://ssh-mitm.at/contact.html">Contact<i class="far fa-address-card ml-2"></i></a>
 </li>