[Travis] Add Ubuntu 20.04, OSX XCode 11.5 jobs

[rajat2004]

No documentation changes until tested, currently Focal build fails due to a Python package trollius not working on Python 3.8, used in ROS somewhere

[saihv]

catkin-tools in Noetic should be using asyncio instead of trollius as it natively works with Python 3.

catkin/catkin_tools#574

Do you have any error logs relating to the trollius errors?

[rajat2004]

Ahh yes, sorry, forgot to put a link to my Travis build, here's the currently running one - https://travis-ci.com/github/rajat2004/AirSim/builds/187740417
And the build before that - https://travis-ci.com/github/rajat2004/AirSim/builds/180634888
Not sure why Travis isn't appearing here though

I didn't dig into this at the time since got busy with other things, will try to look at them more now

[rajat2004]

Yeah, so the problem is still there, seems like there hasn't been a new release of catkin_tools with the trollius fix, should it be installed from the git repo instead?

[saihv]

The latest travis build is still pulling catkin_tools 0.6.1, the async fix is only present in 0.7.0+.

Could you try this?
sudo apt install python3-osrf-pycommon python3-catkin-tools

[rajat2004]

@saihv I thought I had tried out installing from apt earlier, but didn't work. Just tried it out again - https://travis-ci.com/github/rajat2004/AirSim/builds/187934390
Works with 20.04, but breaks 18.04, 16.04. I'll try a bit again to get things working by shifting apt<->pip in places, but I think the easiest way might be to just run the appropriate command for 20.04 separately

As for the pip install, 0.6.1 is the latest release - https://pypi.org/project/catkin-tools/
From this issue - catkin/catkin_tools#594, which is still open, release 0.7.0 has yet to happen

I've added an if-block to install catkin_tools from source on Ubuntu 20.04, Travis build is working - https://travis-ci.com/github/rajat2004/AirSim/builds/187936045
Does this way seem okay, or should something else be done?

[saihv]

This looks good. I guess we'll keep an eye out and unify the scripts once the fixed catkin_tools is released. Thanks for looking into this!

[rajat2004]

Great, thanks for merging!
Documentation can be updated after some testing has been done on Ubuntu 20.04
Could you perhaps have a look at why Travis isn't appearing in the CI checks?