There's been some discussion in #1065 regarding what to do about
refreshing groups. As it stands today dex doesn't update any of the
claims on refresh (groups would just be another one). The main concern
with enabling it is that group claims may change more frequently. While
we continue to wait on the upstream refresh flows, this adds an option
to enable the group claim. This is disabled by default (so no behavioral
change) but enables those that are willing to have the delay in group
claim change to use oidc IDPs.
Workaround to #1065
Some oauth providers return "thin tokens" which won't include all of the
claims requested. This simply adds an option which will make the oidc
connector use the userinfo endpoint to fetch all the claims.
