Migrating off of TravisCI

[drwl]

Github Actions provides a way for us to automatically run CI and cut releases. @ctran has made progress on this. We want to migrate off of Travis as it's redundant.

Happy to collaborate with any folk(s) that want to take this on.

[drwl]

In my research I've found that Github Actions is currently not mature enough yet to handle the needs of the project. Things that would be nice to have:

• caching of ruby images
• being able to select ruby versions

So for the time being TravisCI will be here to stay.

[drwl]

Also need to setup RVM in Github CI to run integration tests.

[olleolleolle]

This seems done, now!