Fix for future versions of python (#911)
Starting python 3.10, the use of - instead of _ will get a warn (see https://bugs.gentoo.org/796281 for reference)
Signed-off-by: Marco Scardovi <marco@scardovi.com>
Python: Update README with information about code formatting
Also, add a `yapf` section to `setup.cfg` to ensure YAPF runs
format code with the Google style.
