Python 2 reached upstream end-of-life in January 2020. In Fedora Rawhide, it's now provided from the compat package `python27`.
Packages that only use Python 2 at build time, like blitz, had a general exception to keep using it in Fedora 31. Now, the dependency should be removed.
It seems that Python 3 support was already merged upstream (for blitz 1.0.2): https://github.com/blitzpp/blitz/pull/145
If it's possible that the Python 2 build dependency won't get removed
in Fedora 33, please let us know; the package will need a FESCo exception.
If you need anything from us, or something is unclear, please mention it here.
Fixed in rawhide