curl --request PUT \
  --url https://api.givebutter.com/v1/campaigns/{campaign}/discount-codes/{discountCode} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "amount": 50.5,
  "items": [
    "<string>"
  ],
  "type": "percentage",
  "active": true,
  "code": "<string>",
  "uses": 2,
  "starts_at": "2023-11-07T05:31:56Z",
  "expires_at": "2023-11-07T05:31:56Z"
}
'

{
  "id": 123,
  "campaign_id": 123,
  "code": "<string>",
  "type": "<string>",
  "amount": 123,
  "used": 123,
  "uses": 123,
  "active": true,
  "total_discount": "<string>",
  "starts_at": "<string>",
  "expires_at": "<string>",
  "created_at": "<string>",
  "updated_at": "<string>",
  "items": [
    "<unknown>"
  ],
  "all_items": true
}