Create shipping method

{
  "isActive": true,
  "name": "New Carrier",
  "project": {
    "id": "1337"
  },
  "carrier": {
    "carrier": {
      "credentials": {
        "basic": {
          "username": "your-username",
          "password": "your-password"
        }
      },
      "serviceUrl": "https://api.example.com",
      "id": "post-ch",
      "product": {
        "id": "post-ch-express",
        "shipmentType": "outbound"
      }
    }
  },
  "printers": {
    "label": {
      "id": "1337"
    },
    "document": {
      "id": "1337"
    }
  }
}