ci: test minimal Python version on Mac OS (backport #1238)

[mergify[bot]]

This is an automatic backport of pull request #1238 done by Mergify. Cherry-pick of 0d112d3e2923491648904bce57d9424a3ea9e582 has failed:

On branch mergify/bp/stable/0.6/pr-1238
Your branch is up to date with 'origin/stable/0.6'.

You are currently cherry-picking commit 0d112d3e.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
    both modified:   .github/workflows/main.yml

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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[mrossinek]

I'm closing this. Since stable since supports 3.7 and we will likely have 0.7 out soon(ish) I do not think we need to backport this change at this time.