Fetch public WebSocket endpoint info

Examples

iex> ExKucoin.WebSocket.Public.endpoint()
%{
  "code" => "200000",
  "data" => %{
    "instanceServers" => [
        %{
          "pingInterval" => 50000,
          "endpoint" => "wss://push1-v2.kucoin.com/endpoint",
          "protocol" => "websocket",
          "encrypt" => true,
          "pingTimeout" => 10000
        }
    ],
    "token" => "vYNlCtbz4XNJ1QncwWilJnBtmmfe4geLQDUA62kKJsDChc6I4bRDQc73JfIrlFaVYIAE0Gv2--MROnLAgjVsWkcDq_MuG7qV7EktfCEIphiqnlfpQn4Ybg==.IoORVxR2LmKV7_maOR9xOg=="
  }
}