docs(readme): fix beta note

[skip ci]

Author: Awk34

readme.md

@@ -19,7 +19,7 @@ Install `yo`, `grunt-cli`/`gulp-cli`, `bower`, and `generator-angular-fullstack`
 npm install -g yo grunt-cli gulp-cli bower generator-angular-fullstack
 ```
 
-> To install the latest 4.0.0 Beta with Webpack support, use `generator-angular-fullstack@webpack`
+> To install the latest 4.0.0 Beta with Webpack support, use `generator-angular-fullstack@beta`
 
 Make a new directory, and `cd` into it:
 ```