REL: v3.8.4

This is the fourth micro release of the 3.8 series.

Highlights of the 3.8.4 release include:

- Enable building against numpy 2.0; released wheels are built against numpy 2
- macosx: Clean up single-shot timers correctly
- Add a draw during show for macos backend
- Fix color sequence data for Set2 and Set3
- gtk: Ensure pending draws are done before GTK draw
- Update "Created with" url in hand.svg
- Avoid modifying user input to Axes.bar
- fix quiver3d incorrect arrow colors