Merge branch 'webhook-merge-request-approval-events' into 'master'

Update webhooks.md with approval events for merge request events

See merge request gitlab-org/gitlab!33358

doc/user/project/integrations/webhook_events.md

@@ -766,7 +766,7 @@ Payload example:
 Merge request events are triggered when:
 
 - A new merge request is created.
-- An existing merge request is updated, merged, or closed.
+- An existing merge request is updated, approved, unapproved, merged, or closed.
 - A commit is added in the source branch.
 
 The available values for `object_attributes.action` in the payload are: