curl --request GET \
  --url https://api.leanrails.com/v1/subscription_items \
  --header 'Authorization: Basic <encoded-value>'

{
  "object": "list",
  "data": [
    {
      "id": "<string>",
      "object": "subscription_item",
      "subscription": "<string>",
      "price": "<string>",
      "livemode": true,
      "created": 123,
      "quantity": 123
    }
  ],
  "has_more": true,
  "next_cursor": "<string>",
  "url": "<string>"
}