Update Drag.dataTransfer to Js.t (#701)

Author: davesnx

src/ReactEvent.re

@@ -161,7 +161,7 @@ module Drag = {
   [@bs.get] external screenY: t => int = "screenY";
   [@bs.get] external shiftKey: t => bool = "shiftKey";
 
-  [@bs.get] external dataTransfer: t => Dom.dataTransfer = "dataTransfer";
+  [@bs.get] external dataTransfer: t => Js.t({..}) = "dataTransfer"; /* Should return Dom.dataTransfer */
 };
 
 module Pointer = {

src/ReactEvent.rei

@@ -152,7 +152,7 @@ module Drag: {
   [@bs.get] external screenY: t => int = "screenY";
   [@bs.get] external shiftKey: t => bool = "shiftKey";
 
-  [@bs.get] external dataTransfer: t => Dom.dataTransfer = "dataTransfer";
+  [@bs.get] external dataTransfer: t => Js.t({..}) = "dataTransfer"; /* Should return Dom.dataTransfer */
 };
 
 module Keyboard: {