Preview upcoming subscription charges

curl --request POST \
  --url https://api.smokeball.com/subscriptions/{id}/preview \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json-patch+json' \
  --header 'x-api-key: <api-key>' \
  --data '{
  "tierId": "8d074e85-4d95-4d9a-8a63-187719470d49",
  "addOnIds": [
    "3c90c3cc-0d44-4b50-8888-8dd25736052a"
  ],
  "promotionId": "<string>",
  "interval": "Monthly"
}'

{
  "immediateProrationPayment": 3,
  "nextBillingCyclePayment": 3,
  "quantity": 3,
  "taxRates": [
    {
      "externalId": "<string>",
      "name": "<string>",
      "description": "<string>",
      "country": "<string>",
      "state": "<string>",
      "rate": 123,
      "behaviour": 0,
      "createdDate": "2023-11-07T05:31:56Z"
    }
  ]
}