docs(README): update ES module hint

README.md

@@ -1,4 +1,4 @@
-> As of version `1.0.0` this library exposes ES modules. Use an ES module aware transpiler such as Webpack, Rollup or Browserify + babelify to bundle it for the browser.
+> As of version `1.0.0` this library exposes [ES modules](http://exploringjs.com/es6/ch_modules.html#sec_basics-of-es6-modules). Use an ES module aware bundler such as [Webpack](https://webpack.js.org) or [Rollup](https://rollupjs.org) to bundle it for the browser.
 
 # diagram-js
 
@@ -57,4 +57,4 @@ __Note:__ We do not generate any build artifacts. Required parts of the library
 
 ## License
 
-MIT
+MIT