add README.md to publish with npm package

Author: raphamorim

package.json

@@ -4,7 +4,8 @@
   "description": "A react-tv-based implementation of Spatial Navigation by Luke Chang",
   "main": "dist/bundle.umd.js",
   "files": [
-    "dist/"
+    "dist/",
+    "README.md"
   ],
   "scripts": {
     "build": "rollup -c",