post https://api.voucherify.io/v1/vouchers/metadata/async
In one request it is possible to update 100 records.
Upserts are not supported.
Returns
Returns 202 HTTP status code on success and id of the scheduled async action. It informs that your request has been accepted and vouchers will be added to the repository asynchronously. To learn about operation status and result, copy the async action id from the API response and use Get Async Action endpoint.