v0.6.2: Python 3.9+ support (fix install on 3.10)

Fix: abi3 minimum lowered from py312 to py39 — one wheel now works on Python 3.9, 3.10, 3.11, 3.12, 3.13, 3.14+.

Previously pip install qvdrs failed on Python 3.10 because wheels required >= 3.12.

pip install qvdrs==0.6.2