Update extension to use APIv4 and EntityRef
This PR updates the automatchinggift extension to use CivCRM's APIv4 instead of APIv3, as well as the newer data type of EntityRef, instead of ContactRef.
This PR updates the automatchinggift extension to use CivCRM's APIv4 instead of APIv3, as well as the newer data type of EntityRef, instead of ContactRef.