Daemon updates SHA of active requests & reruns conflict checks

Updates the sha of any requested, pickme or added branch if the ls-remote sha has changed since the request was made. Emails the request's user of the change of sha.

Will correctly rerun conflict checkers to determine if any new conflicts have arisen or if any conflicts have been resolved.
I don't think we need a different action for these. A request that is currently in conflict and has the sha changed can now conflict with other non-conflicting pickmes.