Retrieves a severity

curl --request GET \
  --url https://api.rootly.com/v1/severities/{id} \
  --header 'Authorization: Bearer <token>'

{
  "data": {
    "id": "e90a9b08-e56c-41a6-9bd7-fb022603395a",
    "type": "severities",
    "attributes": {
      "name": "r6mrm",
      "slug": "r6mrm",
      "description": "Qui fuga ut quos.",
      "severity": "medium",
      "color": "#E58A1F",
      "position": 1,
      "notify_emails": [],
      "slack_channels": [],
      "slack_aliases": [],
      "created_at": "2025-09-01T03:43:23.442-07:00",
      "updated_at": "2025-09-01T03:43:23.442-07:00"
    }
  }
}