Update avatar

{
  "id": 0,
  "title": "string",
  "description": "string",
  "server": "string",
  "tags": [
    "string"
  ],
  "thumbnail": "http://example.com",
  "owner": "string"
}

{
  "error": {
    "message": "You are not logged in.",
    "code": 7,
    "status": 401
  },
  "data": null
}

{
  "error": {
    "message": "You are not authorized to {0}.",
    "code": 8,
    "status": 401
  },
  "data": null
}

{
  "error": {
    "message": "Resource not found.",
    "code": 3,
    "status": 404
  },
  "data": null
}