fix for useDisposable, update some dev deps

[xaviergonz]

According to an update of the react hooks faq:

https://reactjs.org/docs/hooks-faq.html#how-to-memoize-calculations

You may rely on useMemo as a performance optimization, not as a semantic guarantee. In the future, React may choose to “forget” some previously memoized values and recalculate them on next render, e.g. to free memory for offscreen components. Write your code so that it still works without useMemo — and then add it to optimize performance. (For rare cases when a value must never be recomputed, you can lazily initialize a ref.)

This PR uses the recommended approach of lazy initialization, plus makes sure the effect is not re-created when some inputs are given and the effect is manually early disposed

Also updates some dev deps

[xaviergonz]

Btw, I switched useUnmount to useLayoutEffect since it fixed an issue with useDisposable and basically it is being used internally to dispose a reaction (so the disposal doesn't get delayed), just to be on the safe side.

[coveralls]

Coverage remained the same at 100.0% when pulling 3dfd822 on fix-useDisposable into 5f7d9ca on master.

[danielkcz]

Just some small nit-picks, good work otherwise for sure! Thanks.

[danielkcz]

Last small thing. Also, coverage has dropped by 2% because of that production check. Nothing too horrible, but should be fairly easy to fix. Just set a NODE_ENV for the test and revert it after.

[xaviergonz]

done, checks for prod mode and console error an actual error object

[danielkcz]

Thank you very much for the work.