Get floor price by collection

curl --request GET \
  --url https://api.chainbase.online/v1/nft/floor_price \
  --header 'x-api-key: <x-api-key>'

{
  "code": 0,
  "message": "ok",
  "data": {
    "floor_price": 123,
    "symbol": "<string>",
    "updated_at": "<string>"
  }
}