add CI test for lowest supported runtime version of numpy

[aryarm]

Following up on #307 (comment), I added CI tests for the oldest and newest versions of numpy. I chose numpy 1.16 as the oldest compatible version of numpy, since it's the oldest version that still works with python 3.7 and the setup.py file already requires at least 3.7 anyway

Please note that the CI does not test that oldest version against macos or windows, since the runners in the CI use a version of python unsupported by numpy 1.16

[brentp]

Thanks @aryarm for getting this going!

I wonder if @ccwang002 or @tomwhite can have a look. I can't keep up with all these issues.

[tomwhite]

Thanks @brentp and @aryarm! This looks good to me (but I'm finding it hard to keep track too).

My only comment is that oldest-supported-numpy is deprecated now, but we're only using it for older versions of Python (if my reading of https://github.com/brentp/cyvcf2/blob/main/pyproject.toml is correct). Anyway, it seems fine for the moment, but we can probably drop Python 3.7 and 3.8.

Maybe do a release and we can try it out with sgkit?

[aryarm]

Yes, exactly! oldest-supported-numpy is deprecated, but since numpy 2.0 only supports python 3.9+, we still need to build with oldest-supported-numpy for python 3.7 and 3.8

I actually maintain a few packages that depend on cyvcf2, and I know our users would continue to enjoy having support for python 3.7 and 3.8. So personally, I kinda hope that you continue supporting them, but I'm happy to remove support for them in this PR, if you decide it's not worth it

By the way, I added another commit (to test against the newest available versions of numpy with python 3.7 and 3.8 as well). Sorry for the noise!

[tomwhite]

Yes, exactly! oldest-supported-numpy is deprecated, but since numpy 2.0 only supports python 3.9+, we still need to build with oldest-supported-numpy for python 3.7 and 3.8

Got it.

I actually maintain a few packages that depend on cyvcf2, and I know our users would continue to enjoy having support for python 3.7 and 3.8. So personally, I kinda hope that you continue supporting them, but I'm happy to remove support for them in this PR, if you decide it's not worth it

Fine to leave support for them in this PR (as long as they are not blocking the build, which they don't seem to be). They are getting quite old and the ecosystem marches on... Even Python 3.9 is out of the SPEC 0 support window at this point: https://scientific-python.org/specs/spec-0000/