Fix incorrect use of connect/1

Fix incorrect use of connect/1

Hint from Phoenix 1.4.17, which has a connect/7 shim:

lib/phoenix/socket/transport.ex:

  def connect(endpoint, handler, _transport_name, transport, serializers, params, _pid \\ self()) do
    IO.warn "Phoenix.Socket.Transport.connect/7 is deprecated"

    handler.connect(%{
      endpoint: endpoint,
      transport: transport,
      options: [serializer: serializers],
      params: params
    })
  end