textproc/py-griffe: Update to 1.7.2
- Adjust USE=python accordingly, because Python 3.8 is no longer present in the ports tree after ca15850a2b13 while I'm here.
Changelog since 1.7.0:
https://github.com/mkdocstrings/griffe/releases/tag/1.7.2
MFH: 2025Q2