New CI service

[tomdottom]

As mentioned in #23 travis-ci.org is shutting down and making changes to how they support OSS projects.

• Is there current offering for OSS projects enough for pytest-bandit (would it even qualify)?; or
• Should an alternative CI service be considered?

[mattwwarren]

Pulling my comment from the issue here:

Seems like we could try to run with travis-ci.com or set up Actions. I'm tempted to experiment with the latter, which seems to have plenty of boilerplate, but open to influence.