devel/py-asttokens: Fix RUN_DEPENDS: py-six was removed from dependency
- Convert to USE_PYTHON=pep517
- Update version requirement of *_DEPENDS
- Add ASTROID option
- Bump PORTREVISION for dependency and package change
Reference: https://github.com/gristlabs/asttokens/commit/4eebd864eb052884762d0d26bb4db45851568dc9