remove indigo from version dropdown

Author: Alex

_themes/sphinx_rtd_theme/version_dropdown.html

@@ -6,7 +6,6 @@
         <option value="http://ros-planning.github.io/moveit_tutorials/">MoveIt 1 - Noetic</option>
         <option value="" selected>MoveIt 1 - Melodic</option>
         <option value="http://docs.ros.org/en/kinetic/api/moveit_tutorials/html/index.html">MoveIt 1 - Kinetic</option>
-        <option value="http://docs.ros.org/en/indigo/api/moveit_tutorials/html/index.html">MoveIt 1 - Indigo (EOL)</option>
     </select>
     </div>
 </div><br>