Updates details of a shipment plan identified by the shipmentPlanId.
This is a partial update, meaning that only the provided
fields will be updated. If ruleIds field is specified, it will replace
the existing rules currently associated with the shipment plan.

Note:
segments cannot be edited through this API. Changing the order of the segments in a plan
would cause shipments created from earlier versions of the plan diverge from a shipment
instantiated from the new plan with different segment structure. Individual segments can
still be updated via the shipments/v4/plans/{shipmentPlanId}/{segmentPlanId} endpoint.