clarify proxy variable names in readme?
clarify proxy variable names in readme?

The casing for `*_proxy` is currently inconsistent. I'm guessing that's a typo?

Thanks for maintaining this awesome tool!
sebhahn/pyenv,sebhahn/pyenv,pyenv/pyenv,pyenv/pyenv,sebhahn/pyenv,pyenv/pyenv,yyuu/pyenv,yyuu/pyenv