Merge pull request #28 from jhen0409/patch-1

Use esm source as module

Author: nosferatu500

package.json

@@ -3,6 +3,7 @@
   "version": "4.1.4",
   "description": "Drag-and-drop sortable component for nested data and hierarchies",
   "main": "./index.js",
+  "module": "./esm/index.js",
   "types": "./index.d.ts",
   "exports": {
     "./package.json": "./package.json",