allow es6 class rule to be configured to discourage usage as well
allow es6 class rule to be configured to discourage usage as well

lencioni/eslint-plugin-react,yannickcr/eslint-plugin-react,pwmckenna/eslint-plugin-react,AlexKVal/eslint-plugin-react,mathieumg/eslint-plugin-react,petersendidit/eslint-plugin-react