fix(rollup): update rollup configuration

Author: jaebradley

package.json

@@ -2,10 +2,11 @@
   "name": "@jaebradley/example-rollup-react-component-npm-package",
   "version": "0.0.0-development",
   "description": "Example React Component for npm Publication using Rollup",
-  "main": "./build/index.js",
-  "module": "./build/index.es.js",
+  "main": "build/index.cjs.js",
+  "module": "build/index.esm.js",
+  "browser": "build/index.umd.js",
   "files": [
-    "./build"
+    "build"
   ],
   "scripts": {
     "build": "rollup -c",

rollup.config.js

@@ -13,10 +13,15 @@ const config = {
   input: 'src/index.js',
   output: [
     {
-      file: pkg.main,
+      file: pkg.browser,
       format: 'umd',
       name: 'Example',
     },
+    {
+      file: pkg.main,
+      format: 'cjs',
+      name: 'Example',
+    },
     {
       file: pkg.module,
       format: 'es',