git author name & email from git config
Created by: chrispine
Adds a function which uses git config
to find default git author name and email.
This function is untested and unused. I was going to use this as a fallback for when the campaign spec does not include author details. However, we decided we didn't want to do that.
When we implement src campaign create-spec
or whatever we call it, this would be a useful function to have.