doc: add link to workflow in api docs menu

Added link to workflow guidelines page in API docs' navigation menu.

Fixes https://github.com/joyent/node-website/issues/102.

Reviewed-By: Julien Gilli <julien.gilli@joyent.com>
PR-URL: https://github.com/joyent/node/pull/14570

doc/template.html

@@ -30,6 +30,7 @@
           <li><a href="http://nodejs.org/documentation/">About Docs</a></li>
           <li><a href="http://nodejs.org/documentation/tutorials/">Tutorials</a></li>
           <li><a href="http://nodejs.org/documentation/contributing/">Contributing</a></li>
+          <li><a href="http://nodejs.org/documentation/workflow/">Workflow</a></li>
           <li><a href="http://nodejs.org/documentation/localization/">Localization</a></li>
           <li class="active"><a href="http://nodejs.org/api/">API Docs</a></li>
         </ul>