change on push workflow to be a matrix over all supported python versions

[sbillinge]

Only do this on push to main for pure python packages.

[bobleesj]

@Tieqiong Since it's a part of the milestone, will be this implemented after

#123

?

[Tieqiong]

A matrix test workflow is mostly ok, but could be tricky for small things, even for pure python packages.

For example, for Mac platform there's no up to date, usable version of pdffit2 on conda forge, which means for a matrix test we need to specifically ask macOS to uninstall diffpy.pdffit2 (if installed), install gsl, then pip install pdffit2 (see diffpy/diffpy.pdfgui#205).

I can try to write one, but further fixing is going to be needed for sure.

[bobleesj]

Okay, since our current priority is testing the central CI system (#115), let's re-visit this as soon as we are done with it.

[sbillinge]

We can just have the matrix so what doesn't break to begin with. Let's discuss.

[bobleesj]

Can be closed with the new PR Billingegroup/release-scripts#51

[bobleesj]

@sbillinge Could you please close this issue?