Remove vfx platform 2020 support from README.md, add 2024 and 2025, note that 3.12 is also supported

[ssteinbach]

Fixes #1876
Fixes #1804

• Removes VFX Platform 2020 from the badge, adds 2024 and 2025
• stripped out code blocks that indicated they were present for python versions before 3.9.
• Adds notes that Pyhon 3.12 is supported (CI is already running on 3.12, binaries are already built)

As noted in the comments below by @JeanChristopheMorinPerso, this PR doesn't fully cover #1094, it doesn't add any of the VFX platform container related testing stuff.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.72%. Comparing base (c0e97b0) to head (7193bd4).
Report is 54 commits behind head on main.

❌ Your changes status has failed because you have indirect coverage changes. Learn more about Unexpected Coverage Changes and reasons for indirect coverage changes.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1883      +/-   ##
==========================================
+ Coverage   84.11%   84.72%   +0.61%     
==========================================
  Files         198      177      -21     
  Lines       22241    12809    -9432     
  Branches     4687     1191    -3496     
==========================================
- Hits        18709    10853    -7856     
+ Misses       2610     1773     -837     
+ Partials      922      183     -739     

Flag	Coverage Δ
py-unittests	84.72% <ø> (+0.61%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

see 135 files with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c125d9c...7193bd4. Read the comment docs.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[meshula]

Hi Stephan, current vfxplatform year is 2025, we currently claim to support 2023,22,21. Actually it should be cy+3 which means 25,24,23,22. So we should remove 2021 as well. Accordingly this also gives us a bump to python 3.9 so we can at long last drop python 3.7 support.

[ssteinbach]

Added changes in to remove 3.7 and 3.8

[JeanChristopheMorinPerso]

This looks good to me. The only thing that I would add is a mention that we also support 3.12 since we already ship wheels for 3.12 and according to https://clickpy.clickhouse.com/dashboard/opentimelineio?min_date=2024-03-03&max_date=2025-04-20, users effectively depend on 3.12.

Also, a nice side effect of this PR is that it will enable #1816.

[ssteinbach]

@JeanChristopheMorinPerso to be clear, does this PR also address #1094 ?

[JeanChristopheMorinPerso]

@ssteinbach I don't think it does. We aren't really testing against the VFX platform targets like we should, at least on Linux. Doing so would require us to run the tests in docker containers that match the platform years.

[ssteinbach]

Ok got it. I'll leave that issue off this pr, that's a different project.

[JeanChristopheMorinPerso]

@ssteinbach I might be interpreting your comment wrong, but I don't see a note about python 3.12, is this expected?

[ssteinbach]

@JeanChristopheMorinPerso yup! Forgot to push a commit. That is there now too.

[meshula]

lgtm