Get retention cohorts

curl --request GET \
  --url https://api.oneofnone.io/v1/analytics/retention/cohorts \
  --header 'x-api-key: <api-key>'

{
  "meta": [
    {
      "name": "<string>",
      "type": "<string>"
    }
  ],
  "data": [
    {
      "cohort_date": "<string>",
      "period": 123,
      "cohort_size": 123,
      "retained_users": 123,
      "retention_rate": 123
    }
  ],
  "rows": 123,
  "statistics": {
    "elapsed": 123,
    "rows_read": 123,
    "bytes_read": 123
  }
}