python3-greenlet: update to 3.4.0

python3-greenlet: update to 3.4.0

Update package to 3.4.0.

Changes:
- Added binary wheels for RISC-V 64
- Fixed multiple rare crash paths during interpreter shutdown; now uses
  the atexit module (subtle API change: getcurrent unavailable once
  atexit fires)
- Fixed multiple race conditions in free-threaded (no-GIL) builds when
  greenlets are accessed from multiple threads, some causing assertion
  failures or interpreter crashes
- Several minor correctness fixes from automated code audit

Signed-off-by: Alexandru Ardelean <redacted>