Warning 'UNSAFE_componentWillMount', How to fix the problem?

Warning facing whine I am using react-helmet.

Warnings -> `Using UNSAFE_componentWillMount in strict mode is not recommended and may indicate bugs in your code. See https://reactjs.org/link/unsafe-component-lifecycles for details.

• Move code with side effects to componentDidMount, and set initial state in the constructor.

Please update the following components: SideEffect(NullComponent)`