Add canonicalization of python versions
The ci_build parsing will now drop the
revision portion of the requested python
version targets to build for, since users
were passing in old buggy versions.
Using only major.minor will result in the latest
of the minor series being used, and won't affect
any build outputs like bytecode or ABI bindings.
Those are tied to major.minor versions of CPython.
(cherry picked from commit 5bf08753d6da9ef46d2c6b5388dfa68952212816)
