Creates an incident event service

curl --request POST \
  --url https://api.rootly.com/v1/events/{incident_event_id}/services \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/vnd.api+json' \
  --data '{
  "data": {
    "type": "incident_event_services",
    "attributes": {
      "incident_event_id": "<string>",
      "service_id": "<string>",
      "status": "operational"
    }
  }
}'

{
  "data": {
    "id": "8aa1833c-37cc-4fde-8564-b533cbaa2d6c",
    "type": "incident_event_services",
    "attributes": {
      "incident_event_id": "6a3abb60-a067-4aef-89b9-50057e34c387",
      "service_id": "728e1f74-27c7-438f-9a79-defb48d20654",
      "status": "partial_outage"
    }
  }
}