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