Fix pip cache in Github CI by updating an action version

[avidale]

Why ?

Problem: Github CI is failing.
We are getting errors like this one here:

Run actions/setup-python@v3
  with:
    python-version: 3.10
    cache: pip
    token: ***
Successfully setup CPython (3.10.18)
/opt/hostedtoolcache/Python/3.10.18/x64/bin/pip cache dir
/home/runner/.cache/pip
Error: Cache service responded with 400

So we should do something about the pip cache.

How ?

Apparently, we were using an outdated version of the setup-python action. When updating it from v3 to v4, the cache service error goes away.

Test plan

Just look at the CI runs in this PR: they are working again!