REL: prepare release of version 0.12

[theroggy]

List of (open) PR's planned for inclusion: https://github.com/geopandas/pyogrio/milestone/9

Extra things to be considered, or items that need a further push to get them included:

• GDAL 3.11 in wheel?
• Improve Datetime support: ENH: improve support for datetime columns #486

Things probably better kept for 0.13 timing-wise?

• Drop Python 3.9 (and Python 3.10?): MAINT: minimum python version required to 3.10 #557
  • end of live: oktober 2025: https://devguide.python.org/versions/
• Add Python 3.14 support (will require updating the manylinux base, last time this gave troubles)
  • will only be released 7 october 2025
• Drop support for some older GDAL versions
• Drop manylinux2014

[brendan-ward]

We might want to consider dropping manylinux2014 relatively soon too, though we may want to do that in the next release as part of dropping Python 3.9, older GDAL, etc.

[EwoutH]

What's the exact plan/timeline on Python 3.14 support?