Fetch a user permission

Example response

{
  "data": {
    "id": "p2f0ou-3geb4w-123456",
    "relationships": {
      "user": {
        "id": "p0v24p-g7jy9k-123456"
      },
      "permissible": {
        "id": "oqgiju-21olts-ce9egi"
      }
    }
  }
}