Requires update to latest version of react

[emekaorji]

As in #124

This version needs to be updated to support the latest version of react, but it seems as though there's no team behind this anymore. The last update was 2017. It's not ideal to downgrade in order to use react-reveal, So anyone, anyone at all, pls help in updating if you understand the code base and push, perhaps it would be merged Can't find any scroll-reveal library out there