fix: Fix warning since lifecycle method should be componentWillUnmount (#461)
index.js:1446 Warning: App has a method called componentDidUnmount(). But there is no such lifecycle method. Did you mean componentWillUnmount()?
index.js:1446 Warning: App has a method called componentDidUnmount(). But there is no such lifecycle method. Did you mean componentWillUnmount()?