Migrate to GitHub Actions

[jacobtomlinson]

Closes #6787

This PR migrates CI to GitHub Actions.

To do:

• Run tests on all os/python combinations
• Run nightly tests on upstream repos
• Import checks
• Mindeps checks
• HDFS checks

Changes:

• Coverage is only run on linux py38
• All python versions are now tested on macos

[jacobtomlinson]

I think this is ready now.

The mindeps and upstream tests are failing on my fork, but the failures are consistent with the existing failures in Travis. This should probably be investigated but is orthogonal to this migration.

[mrocklin]

Thank you for doing this @jacobtomlinson

@jakirkham or @quasiben is this something that you have time to take a look at? My guess is that you are more familiar with CI than most folks.

[jrbourbeau]

Thanks for all your work on this @jacobtomlinson! I've left a few small-ish comments, but overall the changes here look good

[jrbourbeau]

I'm not 100% sure this is working as the upstream build was skipped for e5e2cd9 which includes "test-upstream" in the commit message

[jacobtomlinson]

It only works for the first commit in the PR (head_commit). I spent some time trying to figure out if you could trigger this on the latest commit on the branch but it doesn't seem the github.event object has this info.

[jacobtomlinson]

Thanks @jrbourbeau I've addressed the review feedback.

I've commented out the coverage for now. I would actually propose that we switch to codecov in future. I've had good experience in other projects and it handles combining coverage very well. So you run coverage on everywhere and codecov merges the reports, this would mean things like the HDFS tests would be included in coverage on master.

But as you say it would be good to address this later.

[gforsyth]

Small changes for the migration from goanpeca -> conda-incubator org

[jrbourbeau]

Thanks for all your work on this @jacobtomlinson!

[jacobtomlinson]

Thanks for the tweaks @gforsyth!