Fix typo in documentation of option env-cache (#466)
Fix typo in documentation of option env-cache (#466)

The text mixed up the two sub-words of the option. In the latest catkin_tools version 0.4.4, the option is named ``env-cache``, not ``cache-env``.
rhaschke/catkin_tools,catkin/catkin_tools,rhaschke/catkin_tools,catkin/catkin_tools,rhaschke/catkin_tools,catkin/catkin_tools,catkin/catkin_tools