curl --request PUT \
  --url 'https://api.stateset.com/api/v1/carts/{id}/items/{item_id}' \
  --header "Authorization: Bearer $STATESET_API_KEY" \
  --header 'Content-Type: application/json' \
  --data '{
  "discount_amount": "5.00",
  "quantity": 2,
  "unit_price": "49.00"
}'

{
  "discount_amount": "5.00",
  "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "name": "Two-Person Tent",
  "product_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "quantity": 2,
  "sku": "SKU-TENT-2P-GRN",
  "total": "102.12",
  "unit_price": "49.00"
}