Update Artist

curl --request PUT \
  --url https://server26-dot-royalti-project.uc.r.appspot.com/artist/{id} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "artistName": "<string>",
  "signDate": "2023-12-25",
  "label": "<string>",
  "externalId": "<string>",
  "links": {},
  "split": [
    {
      "user": "<string>",
      "share": 123
    }
  ]
}'

{
  "message": "Artist updated successfully"
}