Add coupon to subscription

curl --request PUT \
  --url https://app.dynamicauth.com/api/v0/organizations/{organizationId}/billing/subscription/coupon \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "coupon": "An example name"
}'

{
  "billingPortalUrl": "<string>",
  "billingPortalAddPaymentMethodUrl": "<string>",
  "hasPaymentMethod": true,
  "planType": "free",
  "inTrial": true,
  "scope": [
    "<string>"
  ],
  "trialStart": "2023-11-07T05:31:56Z",
  "trialEnd": "2023-11-07T05:31:56Z",
  "trialDaysLeft": 123,
  "currentBillingPeriod": {
    "startDate": "2023-11-07T05:31:56Z",
    "endDate": "2023-11-07T05:31:56Z",
    "usagesCount": 123
  },
  "version": "<string>",
  "shouldLockEnvironmentSwitch": true,
  "coupons": [
    {
      "coupon": "An example name"
    }
  ]
}