rev-branch-cache: add a way to force rewrite of the cache
This seems useful to be able to do this, for example during strip.
This align with the intended expressed in the `test-branches.t` test. This will
help use being more confident about future changes in the series.
# name space package to host third party extensions
from __future__ import annotations
import pkgutil
__path__ = pkgutil.extend_path(__path__, __name__)