Update react/require-extension rule

[tofumatt]

Running npm run lint outputs the deprecation warning:

The react/require-extension rule is deprecated. Please use the import/extensions rule from eslint-plugin-import instead.

We should upgrade to get rid of that warning.

[muffinresearch]

That's not in our code-base, probably we're seeing that via the airbnb rules so this will depend on an upstream update.

[muffinresearch]

Blocked by airbnb/javascript#978

[tofumatt]

Aha, good point. I was gonna see about a simple upstream patch until I saw the amount of things that need changing, we'll just wait on this I guess 😄

[kumar303]

npm run lint no longer shows this warning so it must have been fixed upstream