py3-compat: Simplify output
It now just prints a checkmark or an X instead of the full list of
supported Python 3 versions.
Move Python 3 compatibility checking to standalone script
bash: Check if a package is compatible with Python 3
git: Configure diff driver for gzipped text files
gnupg: Configure default keyserver
dirmngr.conf does not appear to be used, at least not on macOS, so use
bash: New functions to link to Stack docs and coverage reports
bash: New function to easily retrieve AWS secrets
gnupg: Delete agent config
I don't use Linux anymore, so it's not really necessary.