Update Webpack URL (#5454)

Author: Samarth Verma

README.md

@@ -163,7 +163,7 @@ You are now set up to use all ES6 features and React specific syntax.
 
 ### Using webpack
 
-Jest can be used in projects that use [webpack](https://webpack.github.io/) to
+Jest can be used in projects that use [webpack](https://webpack.js.org/) to
 manage assets, styles, and compilation. webpack does offer some unique
 challenges over other tools. Refer to the [webpack guide](docs/Webpack.md) to get
 started.