Update index.d.ts (#42167)
Update index.d.ts (#42167)

Not much to say here, its just missing and I needed it. Is there a reason it already wasn't in?
It's referenced here: https://github.com/atlassian/react-beautiful-dnd/blob/master/docs/sensors/sensor-api.md
georgemarshall/DefinitelyTyped,dsebastien/DefinitelyTyped,markogresak/DefinitelyTyped,georgemarshall/DefinitelyTyped,georgemarshall/DefinitelyTyped,georgemarshall/DefinitelyTyped,dsebastien/DefinitelyTyped,mcliment/DefinitelyTyped