Fix setuptools site.py breakage in Python 3.11, bump gobject-introspection, bump windows image

cerbero: Fix setuptools site.py breakage in Python 3.11

We can use a proper Python virtual env, and it'll work out of the box.
There might be some weirdness with the fact that we use two prefixes:
build-tools and the target prefix, but that might just mean adding
a second site-packages prefix somehow.

In any case, python bindings are disabled right now, so not a blocker.

Fixes #406 (closed)

gobject-introspection.recipe: Bump to 1.74.0

Fixes #403 (closed)

ci: Update windows image to latest

Only the first commit should be backported to 1.20