versioning is an optional header. You need to pass versioning: false header to disable versioning while you are Updating a record. Note that you can disable versioning on Private records only.
[2] JSONbin UPDATE API Reference | JSONbin.io | Free JSON storage and JSON hosting service. Ideal for small scale Web apps, Websites and Mobile apps, , https://web.archive.org/web/20181118155404/http://jsonbin.io/api-reference/bins/update
[3] >>2 では versioning だったものが >>1 の現在の版では
X-Bin-Versioning
に変わっています。