The cgi and cgitb modules are removed with Python 3.13

[dvzrv]

Hi! :wave:

I package this project for Arch Linux. We are currently tracking blockers for Python 3.13 and identified the use of cgi/cgitb as one. With Python 3.13 these modules will be removed: https://docs.python.org/3.13/whatsnew/3.13.html#summary-release-highlights

AFAICT only examples and contrib packages are affected though: https://github.com/search?q=repo%3Anecaris%2Fpython3-openid%20cgi&type=code