getFrom method
Will get a collection of PcoPeoplePerson objects (expecting many)
using a path like this: https://api.planningcenteronline.com/people/v2/message_groups/1/from
Implementation
Future<PcoCollection<PcoPeoplePerson>> getFrom(
{PcoPeoplePersonQuery? query}) async {
query ??= PcoPeoplePersonQuery();
var url = '$apiEndpoint/from';
return PcoCollection.fromApiCall<PcoPeoplePerson>(url,
query: query, apiVersion: apiVersion);
}