fix phoenixchat example

Author: the-mikedavis

examples/phoenixchat_herokuapp.exs

@@ -7,7 +7,7 @@
 http_get_message = receive(do: (message -> message))
 {:ok, conn, [{:status, ^ref, status}, {:headers, ^ref, resp_headers}, {:done, ^ref}]} =
   Mint.HTTP.stream(conn, http_get_message)
-{:ok, conn, websocket} = Mint.WebSocket.new(conn, ref, status, req_headers, resp_headers)
+{:ok, conn, websocket} = Mint.WebSocket.new(conn, ref, status, resp_headers)
 
 {:ok, websocket, data} = Mint.WebSocket.encode(websocket, {:text, ~s[{"topic":"rooms:lobby","event":"phx_join","payload":{},"ref":1}]})
 {:ok, conn} = Mint.HTTP.stream_request_body(conn, ref, data)
@@ -28,6 +28,6 @@ message = receive(do: (message -> message))
 IO.inspect(messages)
 
 message = receive(do: (message -> message))
-{:ok, conn, [{:data, ^ref, data}]} = Mint.HTTP.stream(conn, message)
-{:ok, websocket, messages} = Mint.WebSocket.decode(websocket, data)
+{:ok, _conn, [{:data, ^ref, data}]} = Mint.HTTP.stream(conn, message)
+{:ok, _websocket, messages} = Mint.WebSocket.decode(websocket, data)
 IO.inspect(messages)