build(python)!: drop Python 3.7 support

[stinodego]

Re-opened from #7949

Changes:

• Set required Python version to >=3.8
• Set PyO3 abi3 feature to Python 3.8
• Update CI to run on Python 3.8 instead of 3.7 (for release, test, and mypy jobs).
• Update some typing imports
• Remove some typing workarounds
• Update pandas-stubs version and update some pandas type hints

Notes:

• We still must allow untyped calls for mypy on Python 3.8 due to the backports.zoneinfo package having some issues.

[ritchie46]

I think we can just merge this right? Doesn't need a major/breaking version? Numpy dropped support on version 1.22.

[ritchie46]

Shall we wait another release? 3.7 downloads proportion is still on 40%. :/

[stinodego]

Shall we wait another release? 3.7 downloads proportion is still on 40%. :/

I really wonder where those downloads are coming from 🤔

I'd say let this sit and merge it whenever we're going for the next breaking release. Deal?

[ritchie46]

Yeap, sounds good. Hopefully these downloads are pinned to an older version and would never be updated.

[stinodego]

Yeap, sounds good. Hopefully these downloads are pinned to an older version and would never be updated.

pandas is also still on 40% Python 3.7 downloads, and they have dropped it 6 months ago.

In the end, Polars 0.18.x is still available on Python 3.7. If you want the latest features and fixes, you have to run a supported Python version. I don't see any issue with that.

[mcrumiller]

I really wonder where those downloads are coming from 🤔

They're most likely companies like mine that offer employees software via an in-house software repository that is always way way out of date for "support" reasons. Using no-longer-supported software is the status quo.

[ritchie46]

Ok, let's merge it then!