FormattedRelativeTime: React state update warning

[JanStevens]

Which package?

react-intl: FormattedRelativeTime

Describe the bug

When using FormattedRelativeTime we notice that we receive a React state warning whenever the component gets unmounted (page change for example).

index.js:1 Warning: Can't perform a React state update on an unmounted component. This is a no-op, but it indicates a memory leak in your application. To fix, cancel all subscriptions and asynchronous tasks in a useEffect cleanup function.
    at FormattedRelativeTime

To Reproduce

Codesandbox URL

https://codesandbox.io/s/formattedrelativetime-state-issues-rp0i1?file=/src/index.tsx

Reproducible Steps/Repo

Steps to reproduce the behavior:

1. Open the sandbox
2. Ensure the timer is running
3. Press the button
4. In your console see the error

Expected behavior

FormattedRelativeTime should properly clear up timeouts in useEffect so these errors do not happen

Desktop (please complete the following information):

• OS: MacOS
• Browser: Chrome, Safari, Firefox
• Version: Latest version

Additional context

Using the latest version of react-intl 5.13.4