Can .travis be removed?

[garethahealy]

I don't think it's being used anymore for testing since we have prow but thought I'd check before raising a PR.

• https://github.com/redhat-cop/containers-quickstarts/blob/master/.travis.yml

@pabrahamsson ?

[pabrahamsson]

Yes, we should be good to remove .travis.yml. Prow is doing the all the testing now.