Is your feature request related to a problem? Please describe.
{N} CLI supports yarn, but when you call update script of nativescript-dev-webpack it spawn some npm installs and this cause failures when you run the project after that (with yarn).

Describe the solution you'd like
Detect if {N} CLI use yarn and spawn yarn add instead of npm install.

Describe alternatives you've considered
Lave up to the user to install npm dependencies and do not spawn npm install.