There might be wrong usage in the `examples/basic-with-react-hooks`, that will cause the <Alpha/> component not working.

[Xiao Yuze]

When I try it out the demo using SketchPicker, I found out that the Alpha handle is not working.

After digging for a while I found the usage from the demo is wrong.

// In the demo
const [color, setColor] = useState();
  const handleChange = color => setColor(color);
  return (
    <div className="App">
      <SketchPicker color={color} onChangeComplete={handleChange} />
    </div>
  );

After adding some logs in the source code(helpers/color.js -> toState()), you can see the onChange callback pass a color object to the setColor, which includes a param named hex, and that will cause the toState function to handle it as a pure hex, so the alpha is lost.

It should be used like this:

// In the demo
const [color, setColor] = useState();
  const handleChange = color => setColor(color.rgb);
  return (
    <div className="App">
      <SketchPicker color={color} onChangeComplete={handleChange} />
    </div>
  );