Describe the bug
dev dependencies @angular/compiler-cli and @ngtools/webpack are not updated by nativescript-angular update script

To Reproduce
npm i nativescript@6.0.0 -g
tns create --ng // angular dependencies are ~8.0.0
cd your-app-name
npm i nativescript-angular@8.1.0-next-2019-07-26-145152-01 --save
./node_modules/.bin/update-app-ng-deps

angular dependencies are updated to ~8.1.0
@angular/compiler-cli and @ngtools/webpack are NOT updated

Expected behavior
all angular dependencies should be updated