Add configuration for no-did-update-set-state to allow usage inside condition

As @gaearon has mentioned here and other places, using setState inside componenDidUpdate is acceptable, so long as it's within a conditional check.

Does it seem reasonable to allow a configuration option for this rule to allow setState usage within componenDidUpdate, so long as it's within a conditional check of some kind?

For example, this would pass here:

componentDidUpdate() {
  if (!this.state.isEnabled) {
    this.setState({ isEnabled: true })
  }
}

but this would still fail:

componentDidUpdate() {
  this.setState({ isEnabled: true })
}

An issue here would be that it's still not entirely guaranteed that more complex use cases wouldn't still end up in an infinite loop.