There might be wrong usage in the `examples/basic-with-react-hooks`, that will cause the <Alpha/>  component not working.
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>
  );
```
<img width="2478" alt="WeChat325b7dd1d9b44f7c3884da1396911acd" src="https://user-images.githubusercontent.com/5201649/144401710-69de808a-74b8-45e9-8c64-e10f3b3e9658.png">
<img width="1304" alt="WeChat8d20778a8b3a3c2a70504a42fe1e4bda" src="https://user-images.githubusercontent.com/5201649/144401719-9ca18f76-fdb3-4f0b-860d-5bbc7d2130be.png">

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>
  );
```
