Get Incidents Meta

{
  "statuses": [
    "firing",
    "resolved",
    "acknowledged",
    "merged"
  ],
  "severities": [
    "critical",
    "high",
    "warning",
    "info",
    "low"
  ],
  "assignees": [
    "<string>"
  ],
  "services": [
    "<string>"
  ],
  "sources": [
    "<string>"
  ]
}