Remove `-D` flag from yarn command
Remove `-D` flag from yarn command

There is no need to add this package as a dev dependency. Plus, the instructions don't have such a flag in the `npm` version, so I am not sure why it's inconsistent in the `yarn` version.
anein/angular2-trim-directive,anein/angular2-trim-directive,anein/angular2-trim-directive,anein/angular2-trim-directive