A CLI tool for updating "What To Test" field of the specific build in TestFlight.
$ appstoreconnect-update-whats-new \
--api-id=xxxxxxxxxx \
--api-key-id=xxxxxxxxxx \
--api-issuer=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx \
--private-key=/path/to/private/key/AuthKey_xxxxxxxxxx.p8 \
"This is the message that is used in 'What to Test'"