Document new is_approved attribute

CHANGELOG.md

@@ -10,6 +10,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 - **Breaking:** Changed `mix pleroma.user toggle_confirmed` to `mix pleroma.user confirm`
 - **Breaking**: AdminAPI changed User field `confirmation_pending` to `is_confirmed`
+- **Breaking**: AdminAPI changed User field `approval_pending` to `is_approved`
 - Polls now always return a `voters_count`, even if they are single-choice.
 - Admin Emails: The ap id is used as the user link in emails now.
 - Improved registration workflow for email confirmation and account approval modes.