Migrate testing from travis to github actions?

[rdinnager]

@daijiang I notice that testing is currently handled by travis ci (and the current build seems to be failing?). I think most packages these days use github actions instead. I have used github actions for all my other packages, so I'd be happy to get that setup. What do you think?

[daijiang]

Russell, it would be great if you can move it to GitHub Action. Thanks!