Added support to use the document scroll instead of the element scroll

[mathieumg]

Tried to preserve the style as much as possible. Let me know if anything is out of place.

[nrako]

That's interesting thanks @mathieumg.

Could you please add useDocument prop type with a short comment to the readme, and I'll happily merge your PR.

[nrako]

Also for reference could you please describe in this PR a use case for this where using element scroll isn't sufficient?

[mathieumg]

Thanks! Yes, the use case is the following: The current implementation allows to load more items when you scroll within an element's container, for example a long table with a set height and a overflow-y: scroll CSS property. This PR adds the ability to load more items when the whole page is scrolled and the bottom of the element (minus the treshold) is about to enter the viewport. I think that might even be the most common use case, but I didn't want to make it default to true to break the current API.

I'll update the README shortly!

[mathieumg]

Made the change! Let me know if you want me to squash the commits.

[nrako]

🚀 https://github.com/nrako/react-component-scrollload/releases/tag/0.3.0

[mathieumg]

Awesome, thank you! ✨