You can now tell when an order was last synced with the airline

We've now added a new synced_at field to the Order Schema that tells you when the order being returned was last synced with the airline. This will allow you to tell whether the order being returned is up to date.

We've also updated the Get a single order endpoint to always return an order, even if we can't get the latest data from the airline.

Airlines are always the source of truth for orders, they control the orders and can for example change them without Duffel intervention.

Up until now, in the Get a single order endpoint, we always strived to return an up to date view of the order. When this wasn't possible, for example if the airline returned an error, we would return that error in the form of a HTTP 500.