Fix lint dependencies for Python 3.14

Repro:

- Change 3.13 to 3.14 in .github/workflows/build.yml
- cd software && make lint

Error:

```
cd software && make lint
if [ -d ".venv" ]; then . .venv/bin/activate; fi
python -m isort --diff authbox *.py
python -m black --check authbox *.py
python -m flake8 authbox *.py
All done! ✨ 🍰 ✨
29 files would be left unchanged.
authbox/badgereader_wiegand_gpio.py: "pyflakes[F]" failed during execution due to AttributeError("module 'ast' has no attribute 'Str'")
Run flake8 with greater verbosity to see more details
make: *** [Makefile:44: lint] Error 1
Error: Process completed with exit code 2.
```

ast.Str was [removed in Python 3.14](https://docs.python.org/dev/whatsnew/3.14.html#removed) but something is still using it. Probably need to update a dependency