Retrieves a severity

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

{
  "data": {
    "id": "c902e380-f361-4ee1-b4fb-326cb66ee8d5",
    "type": "severities",
    "attributes": {
      "name": "m1bo8",
      "slug": "m1bo8",
      "description": "Est enim veniam nihil.",
      "severity": "medium",
      "color": "#E58A1F",
      "position": 1,
      "notify_emails": [],
      "slack_channels": [],
      "slack_aliases": [],
      "created_at": "2025-11-21T14:34:29.743-08:00",
      "updated_at": "2025-11-21T14:34:29.743-08:00"
    }
  }
}