curl --request PUT \
  --url https://api.example.com/v1/plus/carts/{id}/items/{item_id}/ \
  --header 'Content-Type: application/json' \
  --data '
{
  "quantity": 2,
  "product": 123,
  "product_company": 123,
  "product_price": 123
}
'

{
  "id": 123,
  "product_name": "<string>",
  "quantity": 2,
  "created_at": "2023-11-07T05:31:56Z",
  "updated_at": "2023-11-07T05:31:56Z",
  "price": "<string>",
  "cart": 123,
  "product": 123,
  "product_company": 123,
  "product_price": 123
}