List workflow executions

{
  "data": [
    {
      "id": "string",
      "workflowId": "string",
      "status": "running",
      "input": {},
      "output": {},
      "startedAt": "2019-08-24T14:15:22Z",
      "completedAt": "2019-08-24T14:15:22Z",
      "steps": [
        {
          "stepId": "string",
          "status": "string",
          "result": {},
          "error": "string"
        }
      ]
    }
  ],
  "pagination": {
    "cursor": "string",
    "hasMore": true
  }
}

{
  "error": {
    "code": "UNAUTHORIZED",
    "message": "Invalid or missing API key"
  }
}

{
  "error": {
    "code": "NOT_FOUND",
    "message": "Resource not found"
  }
}