batches: GitHub.com with SSO has special token requirements

Created by: eseliger

Apparently, when using SSO with GitHub.com, you need to white-list PATs for use on the particular organization first. Otherwise, github rejects requests with a link to authorize that PAT first.

Customer ran into this.

More details here: https://sourcegraph.slack.com/archives/CMMTWQQ49/p1651853501985949

I think this could be as simple as a docs change, educating people about this quirk.