getNextPlan method

Will get a collection of PcoServicesPlan objects (expecting one) using a path like this: https://api.planningcenteronline.com/services/v2/service_types/1/plans/1/next_plan

Implementation

Future<PcoCollection<PcoServicesPlan>> getNextPlan(
    {PcoServicesPlanQuery? query}) async {
  query ??= PcoServicesPlanQuery();
  var url = '$apiEndpoint/next_plan';
  return PcoCollection.fromApiCall<PcoServicesPlan>(url,
      query: query, apiVersion: apiVersion);
}