Update hook_civicrm_apiWrappers

Created by: artfulrobot

Update this to tell people they need to implement api3 and api4 versions of wrapper classes.

Relevant chat links

• https://chat.civicrm.org/civicrm/pl/g7za3irhk7rc5jhek149udityo
• https://chat.civicrm.org/civicrm/pl/iwxgz7bbsir4tb6xsm9zc6rezo