Bearer authentication header of the form Bearer <token>, where <token> is your auth token.
Make sure the date is UTC+0.
To have all planned vouchers terminated on the end of January 2023, the input would be: 2023-01-31T00:00:00.000Z
This can be set only for a date in the future, since goodies vouchers could already have been created.
Example:
Current Date 7th of March -> earliest endDate = 2023-03-08T00:00:00.000Z
Current Date 8th of March -> earliest endDate = 2023-03-09T00:00:00.000Z