Allow using the `read:user` which doesnt have emails available to it

[dpi]

Fixes thephpleague/oauth2-github/issues/24

This is just one way of doing it I suppose. Needs some thoughts on maintainers of thephpleague/oauth2-github

Allows devs to opt out of collecting emails by setting an option.

We could alternatively detect the scopes against a whitelist, automate it without an option.