ci: Drop support for Python 3.8

[dangotbanned]

Closes #3497

Note for reviewers

Most of the changes in this PR were handled by ruff, and relate to these 3.9 changes:

• https://docs.python.org/3.9/whatsnew/3.9.html#type-hinting-generics-in-standard-collections
• https://docs.python.org/3/library/typing.html#deprecated-aliases

Essentially, this looks like a big job but excluding (c765897) this is actually quite a minor PR

Tasks

• Update build.yml, minimum pandas, numpy (da300c3)
• Update pyproject.toml (c694f65)
• Rerun ruff and fix errors (c765897)
  • See (refactor: alt.themes -> alt.theme #3618 (comment))
• Fix ci 3.9 error for ibis (5995202)
  • (https://github.com/vega/altair/actions/runs/11438192554/job/31819283249?pr=3647)
  • Not seeing this locally with hatch test --python 3.9

[dangotbanned]

The CI error is a bit cryptic, but I think #3494 was due to similar error

@MarcoGorelli if you're available, I just wanted to run this by you in case you can spot the issue in

https://github.com/vega/altair/actions/runs/11438192791/job/31819284620?pr=3647

I think it is this line, but quite unsure why this has become an issue here

altair/tests/vegalite/v5/test_api.py

Line 34 in 61f1db7

ibis.set_backend("polars")

Update

Fixed in test: Try invoking ibis.set_backend only in scopes that use it

[dangotbanned]

Not sure how to unblock the expected checks for:

• py 3.8 js 3.0
• py 3.8 js latest

They were removed in da300c3 (#3647)

[dangotbanned]

#3647 (comment)
It seems this was baked into the branch protection rules in #3562 (comment)

Screenshot from that PR (@binste)

I still don't have the permissions for viewing/editing these rules - so I'll need some help updating them if anyone is available?

@mattijn @jonmmease @joelostblom

[mattijn]

I've removed the rules in the rule set for Python version 3.8. All checks are now green, is that in line what is expected? I did not look careful if the CI in this PR was still red before I made the change to the ruleset.

[dangotbanned]

I've removed the rules in the rule set for Python version 3.8. All checks are now green, is that in line what is expected? I did not look careful if the CI in this PR was still red before I made the change to the ruleset.

Thanks @mattijn

It was all green except, with the two 3.8 jobs mentioned in #3647 (comment) marked as expected (but neither pass/failing)
No reds since 5995202 (#3647)

[mattijn]

Is pandas version 1.1.3 the minimum supported version for Python 3.9?

[dangotbanned]

Is pandas version 1.1.3 the minimum supported version for Python 3.9?

That was the earliest I found going through the release notes @mattijn

• https://pandas.pydata.org/docs/whatsnew/v1.1.3.html
• https://numpy.org/devdocs/release/1.19.3-notes.html

I think numpy had some level of support before 1.19.3, but it looked like more of an announcement in that version

[mattijn]

Thanks! Moving forward🥳