## Problem
On Debian 12 (Bookworm), Python 3.11 is the latest available version.
## Summary of changes
- Update Python to 3.11 in build-tools
- Fix ruff check / format
- Fix mypy
- Use `StrEnum` instead of pair `str`, `Enum`
- Update docs
python based regression test setup for auth_broker. This uses a http
mock for cplane as well as the JWKs url.
complications:
1. We cannot just use local_proxy binary, as that requires the
pg_session_jwt extension which we don't have available in the current
test suite
2. We cannot use just any old http mock for local_proxy, as auth_broker
requires http2 to local_proxy
as such, I used the h2 library to implement an echo server - copied from
the examples in the h2 docs.
