Switch back to actions/setup-python

[colesbury]

I think this is finally supported upstream in https://github.com/actions/setup-python, although it's not yet in a release.

We may want to switch users back to actions/setup-python and archive this repository.

[rgommers]

Finally, congrats on getting that over the finish line - that took some patient effort!

Seems like a good idea; it's probably already better to pin a commit on main for upstream setup-python rather than wait for a release.

We should update the README before archiving. If we do that, let's include (a) the syntax for the minimum commit to pin, and (b) the expected first release that will include support.

Does that sound good?

[ngoldbaum]

it's probably already better to pin a commit on main for upstream setup-python rather than wait for a release.

Do you happen to know whether dependabot will update a workflow that is pointing at a non-released commit? If so then I agree with this. If not then we'll need to make sure to update again from e.g. 9e62be8 when setup-python does the next release.

[rgommers]

Not 100% sure if Dependabot won't try to downgrade it (don't think so, but worth checking). It should be upgrading on new releases; it's just pinning to a commit after all.