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