Fix/typings export (wix#719)

* point to index.js to avoid typing reference issues

* define types instead of typings in package.json

Author: ethanshar

index.js

@@ -1,4 +1,4 @@
 // import * as UILIB from './src/index';
 // module.exports = {...UILIB};
 
-module.exports = require('./src/index').default;
+module.exports = require('./src/index.js').default;

package.json

@@ -2,7 +2,7 @@
   "name": "react-native-ui-lib",
   "version": "4.2.0",
   "main": "index.js",
-  "typings": "index.d.ts",
+  "types": "index.d.ts",
   "author": "Ethan Sharabi <[email protected]>",
   "homepage": "https://github.com/wix/react-native-ui-lib",
   "license": "MIT",