docs(readme): it's no longer necessary to use ".default", the export object is the plugin itself now

Author: djcsdy

README.md

@@ -59,7 +59,7 @@ Module:
 Include something like the following in `webpack.config.js`:
 
 ```js
-const ResolveTypeScriptPlugin = require("resolve-typescript-plugin").default;
+const ResolveTypeScriptPlugin = require("resolve-typescript-plugin");
 
 exports = {
     module: {