{
  "summary": "Update a custom field",
  "method": "PUT",
  "path": "/v4/custom_fields/{id}",
  "tag": "Custom Fields",
  "request_body": {
    "label": "string"
  },
  "response": {
    "custom_field": {
      "id": 1,
      "name": "string",
      "key": "string",
      "label": "string"
    }
  }
}