Broader git ignore for pytest cache files (#5361)
Broader git ignore for pytest cache files (#5361)

Make gitignore take pytest cache directories in to account, even if
they reside in subdirectories.

If pytest is run for a certain module, ie. `pytest certbot-apache` the
cache directory is created under `certbot-apache` directory.
letsencrypt/letsencrypt,lmcro/letsencrypt,stweil/letsencrypt,lmcro/letsencrypt,stweil/letsencrypt,letsencrypt/letsencrypt