python-compat: drop support for Python3.6 and 3.7
As discussed on the mailing list¹, these are old version that seems safe to
drop. Python 3.8 comes with various improvement especially regarding typing
capabilities.
[1] https://lists.mercurial-scm.org/pipermail/mercurial-devel/2024-July/297998.html
# name space package to host third party extensions
import pkgutil
__path__ = pkgutil.extend_path(__path__, __name__)