Eslint-plugin-react: Rule to prevent `static PropTypes`

[rsolomon]

I've noticed this a few places, where people are recording propTypes under a static PropTypes member instead of the correct camelCase static propTypes. It would be helpful if there were a lint rule that checks for this, as using PropTypes doesn't fail, it just silently doesn't check.

[ljharb]

That sounds like a good idea. It should probably check for any case variant of propTypes and defaultProps and contextTypes etc, and ensure that none of them exist unless they're the proper casing.

[ljharb]

We could call it no-static-typos or something

[jseminck]

I will take a look at this.

[DianaSuvorova]

@ljharb I think this issue should be closed.

[ljharb]

(Fixed in #1209)