Add node modules and new code for release (#39)

Co-authored-by: tbarnes94 <tbarnes94@users.noreply.github.com>

node_modules/react-is/index.js

@@ -0,0 +1,7 @@
+'use strict';
+
+if (process.env.NODE_ENV === 'production') {
+  module.exports = require('./cjs/react-is.production.min.js');
+} else {
+  module.exports = require('./cjs/react-is.development.js');
+}