getRefund method
Will get a collection of PcoGivingRefund objects (expecting many)
using a path like this: https://api.planningcenteronline.com/giving/v2/donations/1/refund
Implementation
Future<PcoCollection<PcoGivingRefund>> getRefund(
{PcoGivingRefundQuery? query}) async {
query ??= PcoGivingRefundQuery();
var url = '$apiEndpoint/refund';
return PcoCollection.fromApiCall<PcoGivingRefund>(url,
query: query, apiVersion: apiVersion);
}