IE11 Support

[AmonHouston]

Describe the bug Importing react-sortablejs doesn't work on IE11 but does in other browsers, Runs into numerous unsupported functions (finds,includes etc). I can polyfill to fix the finds issue, but it doesn't seem like the includes function can be fixed.

To Reproduce

create a new react app. add react-sortablejs create a simple draggable list drag first item in IE11 (this works) unable to drag any additional items, logs show object doesn't support find or includes

Expected behavior adding polyfills to fix IE11 issue. Sortablejs standard seems to work in IE11 without issue.

Additional notes

It also seems like this page breaks in IE11 https://sortablejs.github.io/react-sortablejs/ with a different error than what i'm experiencing.