Update order items quantity

put https://partners.deliveroo.com/api/v2/picking/orders/{order_id}

Summary

Allows the partner to update the quantities for order items. The endpoint accepts amendments for multiple items in a single
call. It is recommended that the integrating partner batches all the substitutions for an order in a single call
of this endpoint in order to avoid receiving a rate limit exceeded error.

Usage scenario

Site would like to change quantities of order items and fulfill order partially.
Once quantities are amended order can be accepted.

Business constraints

Order has to be in the PLACED status.
An item (identified by id) can be amended only once.
The final_quantity value has to be less than the original quantity value.
Unchanged items are not allowed in the request.

Operational constraints

There's a rate limit of 1 request per order per 30 seconds. If you get over the limit, you'll get "Too many requests" error.