This PR is an attempt to migrate (at least partially) the Windows CI tests over to GitHub Actions. Appveyor runs one job at a time, whereas GH Actions supports up to 20 concurrent jobs, so this should speed up unit tests and help keep them all in one place!
Merge Checklist
[ ] the PR has been reviewed and all comments are resolved
PR Description
This PR is an attempt to migrate (at least partially) the Windows CI tests over to GitHub Actions. Appveyor runs one job at a time, whereas GH Actions supports up to 20 concurrent jobs, so this should speed up unit tests and help keep them all in one place!
Merge Checklist
closes #<issue-number>
to automatically close an issue