[Bf-committers] Moving to Python-3.8

[Campbell Barton]

Hi, Python-3.8 has just been released, with general optimizations and
improvements. Some of these are useful for Blender scripting, others
are general quality-of-life improvements.
I see no reason to stick to Python-3.7x for Blender-2.82 release.

The changes to Blender have been made in both
'master' and 'blender-2.81-release' branches.

I'd suggest we prepare Python-3.8 builds soon,
switching over to using it after Blender-2.81 release is out.

https://docs.python.org/3/whatsnew/3.8.html