Check old decision before a specific time
    
    The decision endpoint allows to pass results and waivers IDs lists to ignore
    (ignore_result, ignore_waiver). These are used to compare the new decision
    with older one. In case of multiple new results or waivers there could be a
    race condition. This change introduces new parameters results_since and
    waivers_since, used to determin the decision before these specific dates.
    This solves the race conditions. ignore_result and ignore_waiver are not
    used anymore to gather the old decision, but they are still parameters of the
    API for backwards compatibility.