fix #3

[paraflu]

I've overrided the didUpdateWidget and seem work.

@override
  void didUpdateWidget(covariant oldWidget) {
    print("didUpdateWidget json ${widget.json}");
    print("didUpdateWidget data: $_data");
    _data = jsonDecode(widget.json);
    super.didUpdateWidget(oldWidget);
  }

[henry-hoang-91]

It only works if edit mode is tree, for support text mode you must update also value in _controller :

_controller.text = _stringifyData(_data, 0, true);

completed code:

@override
  void didUpdateWidget(covariant oldWidget) {
    print("didUpdateWidget json ${widget.json}");
    print("didUpdateWidget data: $_data");
    _data = jsonDecode(widget.json);
    _controller.text = _stringifyData(_data, 0, true);
    super.didUpdateWidget(oldWidget);
  }