Allow ncu-team sync to run in GitHub Actions

[nschonni]

In order to setup a GitHub Action to auto-PR changes, the ncu-team command seems to need the more interactive config/login that I couldn't figure out a way of getting around.

Maybe just a documentation issue, but I couldn't figure out how to get it to either accept the built-in GitHub Actions secret token, or how one might be provided so an auto-PR could be created.