Is your feature request related to a problem? Please describe.
{N} CLI supportsyarn, but when you call update script ofnativescript-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 spawnyarn add instead ofnpm install.

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