Update top navigation: simplify GitHub item, remove Blog

Author: anssiko

_includes/header.html

@@ -43,19 +43,8 @@
               </li>
               <li class="menu-item"><a class="link link--dia" href="{{ 'incubations' | relative_url }}">
                   Incubations</a></li>
-              <li class="menu-item"><a class="link link--dia" href="{{ 'blog' | relative_url }}">Blog</a></li>
               <li class="menu-item"><a class="link link--dia" href="{{ 'community' | relative_url }}">Community</a></li>
-              <li class="menu-item">
-                <a class="link link--dia faq" href="https://github.com/webmachinelearning/">GitHub</a>
-                <ol class="sub-menu">
-                  <li class="menu-item"><a href="https://github.com/webmachinelearning/webnn-polyfill">WebNN
-                      Polyfill</a></li>
-                  <li class="menu-item"><a href="https://github.com/webmachinelearning/webnn-samples">WebNN Samples</a>
-                  </li>
-                  <li class="menu-item"><a href="https://github.com/webmachinelearning/awesome-webnn">Awesome WebNN</a>
-                  </li>
-                </ol>
-              </li>
+              <li class="menu-item"><a class="link link--dia" href="https://github.com/webmachinelearning/">GitHub</a></li>
               <!-- <li class="menu-item"><a class="link link--dia faq" href="{{ 'faq' | relative_url }}">FAQ</a></li> -->
             </ol>
           </nav>