Consider switching away from Travis CI

[niklas88]

I really appreciate the free and easy to use service and feel like enabling Travis CI on this repository has had very positive and valuable effects.

Nevertheless I've grown increasingly frustrated with Travis CI

• On a handful of ocassions Travis CI builds just failed and had to be manually restarted. Most often because of unreachable apt mirrors. I truly hope Travis is running their own mirrors but I doubt it
• The Travis team seems unwilling or possibly incapable of maintaining their build systems. It's been over 2 years since the release of Ubuntu 16.04 and 4 months since the release of Ubuntu 18.04. And yet neither is available as a build environment. One could use them in docker on their 14.04 systems but then that means putting docker commands in .travis.yml which seems to go against the whole point. Instead of listening to their users the Travis team has locked the issue and shows no indication of actively working on this very basic feature.

Given the above I've very little trust in Travis CI as a viable option for the future. So let's discuss alternatives.