Add info from awscli brew caveats to pip3-packages install script.
Add info from awscli brew caveats to pip3-packages install script.

The homebrew formula's "Caveats" section contains useful information
about getting started. Include this information in pip3-packages
where awscli is actually installed.

alphabetum/dotfiles,alphabetum/dotfiles,alphabetum/dotfiles,alphabetum/dotfiles