CI: use pipx and build to simplify and remove a workaround
- [ ] closes #xxxx
- [ ] tests added / passed
- [ ] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [ ] whatsnew entry


This cleans up the SDist build slightly. First, it uses PyPA's "build" instead of directly calling `setup.py`, which will respect PEP 518 requirements and avoids the workaround of installing NumPy to be able to run setup.py. It also uses pipx to avoid needless setup; PyPA's pipx is provides as a first-class package manager on GitHub Actions (and Azure, they share images).

> PyPA's pipx is provides as a first-class package manager on GitHub Actions (and Azure, they share images).

this doesn't help as the archives are not generated here (they are actually justed tested here). sure i suppose we could move to this workflow, but that should happen in conjuction with a change like this. Where are the SDist's built? https://github.com/MacPython/pandas-wheels only does wheels, AFAICT.

Also, this is still testing that the artifact builds and is installable, it's just using better infrastructure for doing so without manual workarounds in producing them. This pull request is stale because it has been open for thirty days with no activity. Please update or respond to this comment if you're still interested in working on this. @simonjayhawkins do we have any manual process in the release for sdists? i don't recall if this changed recently. note completely averse here but this would need to address comments & rebase Thanks for the PR, but it appears to have gone stale. If interested in continuing please merge the main branch, address the review, and we can reopen. I've rebased, but you can't reopen a PR after force pushing to it (IIRC).  I think this was stuck because there was some "manual/other release process" that also needed updating but I wasn't pointed to that. Ah okay. Yes I see we can't reopen this PR (we also don't recommend force pushing to branch as it makes the commit history and changes harder to view).

If you'd like to continue with a new PR we can try to contact the right person who has set up sdist. There weren't really any changes yet, it was just tracking the current main. I can retry. > @simonjayhawkins do we have any manual process in the release for sdists? i don't recall if this changed recently.

yes, the sdist is created locally during the release process and then uploaded to the github release artifacts so that conda-forge can use it and also uploaded to PyPI

> Where are the SDist's built? https://github.com/MacPython/pandas-wheels only does wheels, AFAICT.

https://github.com/pandas-dev/pandas-release

and the conda recipe that points to the manually created sdist uploaded as a github release artifact is at 

https://github.com/conda-forge/pandas-feedstock

