Update an override shift

curl --request PUT \
  --url https://api.rootly.com/v1/override_shifts/{id} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/vnd.api+json' \
  --data '{
  "data": {
    "type": "shifts",
    "attributes": {
      "user_id": 123
    }
  }
}'

{
  "data": {
    "id": "12a41a6d-d389-4342-a5f1-18f7c7e8784d",
    "type": "shifts",
    "attributes": {
      "schedule_id": "54f958da-83f4-4503-8f34-a678fa436518",
      "rotation_id": "cc7ed676-81ed-4c54-985f-6f2729f44e2d",
      "starts_at": "2025-09-11T07:33:11.000-07:00",
      "ends_at": "2025-09-11T15:33:11.000-07:00",
      "is_override": true
    },
    "relationships": {
      "shift_override": {
        "data": {
          "id": "2aabd4fd-8804-478c-a88f-4069d83f724b",
          "type": "shift_overrides"
        }
      },
      "user": {
        "data": {
          "id": "372",
          "type": "users"
        }
      }
    }
  }
}