switch to python qrcode

[anarcat]

python-qrencode is not in great shape. it hasn't seen a release in 3 years and just crashes in python 3.10 because of a cython api change (Arachnid/pyqrencode#14).

python-qrcode is much better maintained and doesn't suffer from those problems. it's used successfully by the qr-backup project, see https://github.com/lincolnloop/python-qrcode

[kamalmostafa]

This issue breaks paperbackup completely for Ubuntu 22.04 (python-3.10) and most other modern OS versions.

... SystemError: PY_SSIZE_T_CLEAN macro must be defined for '#' formats

My Dockerfile pull req works around it by forcing python-3.9 but addressing the root problem should be a high priority, IMHO.