new feature: fill InputDecoration with background color

[robertoltrocha]

Hi, Could you add this options isFilled to fill background-color TextField?

I would like to change background-color of field edit area.

thanks

"CardSettingsField"

 content: TextField(
        controller: _controller,
        focusNode: widget.focusNode,
        keyboardType: widget.keyboardType,
        textInputAction: widget.inputAction,
        textCapitalization: widget.textCapitalization,
        enabled: widget.enabled,
        readOnly: !widget.enabled,
        style: contentStyle(context, value, widget.enabled),
        decoration: InputDecoration(
_**//add this line**_
filled: widget.isFilled,

          contentPadding: widget.contentPadding,
          border: InputBorder.none,
          errorText: errorText,
          prefixText: widget.prefixText,
          hintText: widget.hintText,
          isDense: true,
        ),

[robertoltrocha]

I changed theme and works,