ColorWrapped saturation block pointer jumps erratically in newer versions of React (16.3+)
## Problem

In newer versions of React (16.3+), dragging the saturation block pointer (within a `ColorWrap`) vertically near the bottom causes the pointer to jump horizontally:

**Expected behavior** ([CodeSandbox demo](https://codesandbox.io/s/react-color-16-fep2s?file=/src/App.js))

In this CodeSandbox, React v16 is used. Dragging the saturation block pointer vertically near the bottom doesn't cause the pointer to jump erratically.

<img width="500" src="https://user-images.githubusercontent.com/1811365/101785383-86caeb80-3ab1-11eb-9f17-3ba9539e2424.gif" />

**Unexpected behavior** ([CodeSandbox demo](https://codesandbox.io/s/react-color-1614-clt1u?file=/src/App.js))

In this CodeSandbox, React v16.15 is used. Dragging the saturation block pointer vertically near the bottom causes the pointer to jump erratically.

<img width="500" src="https://user-images.githubusercontent.com/1811365/101785347-7f0b4700-3ab1-11eb-8fac-a6a7f5999b99.gif" />

I'm not sure what is the root problem. But it seems to stem from the `getDerivedStateFromProps` static method. I looks like there is no 

## Potential solution

The `getDerivedStateFromProps` method seems to be deriving an inaccurate next state. By removing this completely, the `ColorWrap` works just fine with an accurate state — the saturation block would no longer jump around erratically. There appear to be no regressions.

## Related pull request

#791 