Change strategy regarding storing credentials ?

[statnmap]

A couple of things that occurred to me while working on this PR:

• I wonder if we ought to encourage users to use a different strategy for storing their PAT than hard coding them in .Renviron? Could {secret}, {cyphr} or {keyring} maybe be used?

UPDATE: I can see that recommendations in {gh} are in line with what I was thinking here. They use {gitcreds}, but as far as I can see that is GitHub only (at the moment at least)