uniqueness should be based off email and not user login

[ladams-bah]

Billing de-duplication is based on the user's primary email address. I believe this script is basing uniqueness off 'User login'. This script would need to reference the 'Last pushed email' column, but I can tell from our reports that this column sometimes does not exactly match the user's primary email address (e.g. *@users.noreply.github.com) so a bit of regex may be needed.