Allow disabling pure component check

[GeKorm]

Hello, thanks for making this great package!

It would be great if there was an option to disable the 'Component is impure and will ALWAYS update when a component above it does' check.

Having every component be pure isn't optimal, since components that need to update often are going through unnecessary shouldComponentUpdate checks. More discussion here.
It's not a huge thing, but for components that are intentionally left as impure, the console warning is impossible to mute without excluding the component from other useful checks.

Thank you