Take no action if already authenticated?

[cboettig]

Proposed change

Currently consecutive runs create a fresh token each time regardless of whether a valid token is already available. While this may be necessary in some cases, this behavior can be confusing especially to newcomers.

Who would use this feature?

This could be particularly useful to students, but could also pave the way for tighter integration with other applications -- e.g. it would be possible for a Git interface (like maybe the one built into JupyterLab?!) to automatically call gh-scoped-creds and have it prompt for login if and only if that login were actually needed.

(Optional): Suggest a solution

I think it would be better if the application were able to first perform a test to see if a valid (non-expired) token already existed, and only initiate the request for a new token if the current token has expired or none is found. Ideally an optional argument like --force could force renewal (the current behavior).