Switch macOS CI to GitHub Actions

[pquentin]

The macOS tests are the current bottleneck, which is why I'm moving them first. I've simply copy-pasted my work from https://github.com/python-trio/hip/blob/master/.github/workflows/ci.yml. GitHub Actions is nice because it gives up to 20x parallelism and is better integrated with GitHub, however the UI is barely usable when the tests are still running. Good news: a codecov token is no longer required.

[codecov]

Codecov Report

Merging #1839 into master will not change coverage by %.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master     #1839   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           22        22           
  Lines         2007      2007           
=========================================
  Hits          2007      2007           

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[pquentin]

I guess I should have opened this one from a branch in the main repo, as GitHub Actions can't be activated on the first pull request.

You can see the tests running here: https://github.com/pquentin/urllib3/actions/runs/68378346

[sethmlarson]

Sweet, great work here! Looking forward to being able to completely delete the _travis and appveyor folders. Once we get our first run I'll add the necessary "required" checks for the master branch to the repo.

[sethmlarson]

Also I enabled Actions, they were previously disabled. Maybe that's why things didn't show up here?

[pquentin]

Hm, did not work yet. Let's try merging this, we can always revert.

[pquentin]

It worked! https://github.com/urllib3/urllib3/actions/runs/68722383 We'll need to update our badges list. Not sure if Travis can go fully away as I don't know how to run PyPy or 3.9-dev in Actions.