Get observations for a series

curl --request GET \
  --url https://api.vintl.io/v1/series/{id}/observations \
  --header 'X-API-Key: <api-key>'

{
  "object": "observation_series",
  "request_id": "<string>",
  "status": "<string>",
  "as_of": "2023-12-25",
  "series": {
    "id": "<string>",
    "title": "<string>",
    "frequency": "<string>"
  },
  "results": [
    {
      "date": "2023-07-01T00:00:00Z",
      "value": "22491.567",
      "as_of_date": "2023-10-26T00:00:00Z",
      "series_id": "GDPC1",
      "unit": "lin",
      "frequency": "Q",
      "source": "FRED"
    }
  ],
  "results_count": 123,
  "has_more": true,
  "next_cursor": "<string>"
}