Get subscription promotions

curl --request GET \
  --url https://api.smokeball.com/subscriptions/{id}/promotions \
  --header 'Authorization: <api-key>' \
  --header 'x-api-key: <api-key>'

[
  {
    "id": "b471682e-fa17-4e46-b7fe-9b2b8fdcb3c2",
    "href": "<string>",
    "relation": "<string>",
    "method": "GET",
    "self": {
      "id": "<string>",
      "href": "<string>",
      "relation": "<string>",
      "method": "GET"
    },
    "productSuite": "<string>",
    "tiers": [
      {
        "id": "b471682e-fa17-4e46-b7fe-9b2b8fdcb3c2",
        "href": "<string>",
        "relation": "<string>",
        "method": "GET",
        "self": {
          "id": "<string>",
          "href": "<string>",
          "relation": "<string>",
          "method": "<string>"
        },
        "smokeballId": "<string>",
        "productSuite": "<string>",
        "name": "Intake",
        "description": "<string>",
        "trialPeriodDays": 123,
        "prices": [
          {
            "default": true,
            "active": true,
            "type": "Recurring",
            "name": "\"$109 per user/month\"",
            "amount": 5900,
            "interval": "Monthly"
          }
        ],
        "createdDate": "2022-04-23T14:00:00Z",
        "updatedDate": "2022-04-23T14:00:00Z"
      }
    ],
    "addOns": [
      {
        "id": "b471682e-fa17-4e46-b7fe-9b2b8fdcb3c2",
        "href": "<string>",
        "relation": "<string>",
        "method": "GET",
        "self": {
          "id": "<string>",
          "href": "<string>",
          "relation": "<string>",
          "method": "<string>"
        },
        "smokeballId": "<string>",
        "productSuite": "<string>",
        "name": "Intake",
        "description": "<string>",
        "trialPeriodDays": 123,
        "prices": [
          {
            "default": true,
            "active": true,
            "type": "Recurring",
            "name": "\"$109 per user/month\"",
            "amount": 5900,
            "interval": "Monthly"
          }
        ],
        "createdDate": "2022-04-23T14:00:00Z",
        "updatedDate": "2022-04-23T14:00:00Z"
      }
    ],
    "usage": [
      "<string>"
    ],
    "name": "Summer Sale 2024",
    "description": "Summer Sale 2024",
    "durationDays": 7,
    "amountOff": 2000,
    "percentOff": 20.5,
    "active": true,
    "numUsed": 42,
    "createdDate": "2024-01-15T10:00:00Z",
    "expirationDate": "2024-12-31T23:59:59Z",
    "codes": [
      {
        "id": "promo_code_1234",
        "name": "SUMMER2024",
        "description": "100% discount!",
        "code": "SUMMER2024",
        "active": true,
        "minimumAmount": 5000,
        "firstTimeCustomersOnly": true,
        "limit": 100,
        "createdDate": "2024-01-15T10:00:00Z",
        "expiratonDate": "2024-12-31T23:59:59Z",
        "metadata": {}
      }
    ],
    "metadata": {},
    "isPersistent": true,
    "isFree": true,
    "deleted": true
  }
]