Summary:
As designed in https://grist.quip.com/fZSrAnJKgO5j/Add-or-Update-Records-API
Current `POST /records` adds records, and `PATCH /records` updates them by row ID. This adds `PUT /records` to 'upsert' records, applying the AddOrUpdate user action. PUT was chosen because it's idempotent. Using a separate method (instead of inferring based on the request body) also cleanly separates validation, documentation, etc.
The name `require` for the new property was suggested by Paul because `where` isn't very clear when adding records.
Test Plan: New DocApi tests
Reviewers: jarek
Reviewed By: jarek
Differential Revision: https://phab.getgrist.com/D3251
0de0cb0f4a