Próxima Fatura

curl -G https://api.upag.io/v1/invoices/upcoming \
  -H "Authorization: Bearer {token}" \
  -d subscription=sub_abc123xyz

{
  "subscriptionId": "sub_abc123xyz",
  "customerId": "cus_ahwDXrgYvur89iPs",
  "currency": "BRL",
  "periodStart": "2024-12-15T10:00:00.000Z",
  "periodEnd": "2025-01-15T10:00:00.000Z",
  "amountDue": 9900,
  "items": [
    {
      "productId": "prod_xyz789abc",
      "priceId": "price_def456ghi",
      "name": "Plano Pro",
      "amount": 9900,
      "quantity": 1,
      "total": 9900
    }
  ]
}