Fix empty `author` field in amendment API endpoints.

4 jobs for master in 43 seconds (queued for 1 second)
Status Job ID Name Coverage
  Doc
passed #114239
doc:api

00:00:15

passed #114240
doc:graphs

00:00:15

 
  Pages
passed #114241
pages

00:00:26

 
  Deploy
passed pages:deploy

00:00:00