useEffect not cancelling timeouts.

[revickulous2001]

I have just installed this project, and I am receiving the following error/warning:

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.
in Toast (created by ToastContainer)

This seems to be due to the fact that the timeouts aren't cancelled in the useEffect hook in the Toast component.

[anmdotdev]

Fixed in v4.2.2