Bump download/upload artifact gha version

[bjlittle]

🚀 Pull Request

Description

Require to bump the version of the download-artifact and upload-artifact to the latest version (@3 -> @4) consistently within the same pull-request.

[pp-mo]

As we've seen the basic v3-to-v4 changes is that artifacts are now immutable and non-rewritable

So I think the problem here is probably that the artifact name must be different for each usage,
so, something like pypi-artifacts-${{ matrix.os }}-${{ matrix.arch }} might work ?

It seems like that, now we are storing different ones in different places, the other tasks will also probably need updating? TBH I'm a bit out of my depth with this.

[bjlittle]

Yeah, there is now no artifact merging and names have to be unique

[bjlittle]

Reference:

• https://github.com/actions/upload-artifact/tree/v4#not-uploading-to-the-same-artifact 😢
• Note about actions/upload-artifact@v4 pypa/cibuildwheel#1699
• Provide guidance for workflows broken by @4? actions/upload-artifact#472

[bjlittle]

I think the best option here for cf-units is not to migrate to v4 for upload-artifact and consequently download-artifact due to the breaking change behaviour introduced.

I recommend that we sit tight and wait for the dust to settle, as community pressure may force a change or a documented best practice pattern may emerge for the common cf-units use case with cibuildwheels with a matrix of distros for wheels and sdist.