curl --request POST \
  --url https://app.flowglad.com/api/v1/product-features \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '{
  "productFeature": {
    "productId": "<string>",
    "featureId": "<string>",
    "expiredAt": "<string>"
  }
}'

{
  "productFeature": {
    "id": "<string>",
    "createdAt": "<string>",
    "updatedAt": "<string>",
    "createdByCommit": "<string>",
    "updatedByCommit": "<string>",
    "livemode": true,
    "productId": "<string>",
    "featureId": "<string>",
    "organizationId": "<string>",
    "expiredAt": "<string>"
  }
}