upgrade-ng.readme

according to https://update.angular.io/

https://update.angular.io/#6.0:7.0

(did not do anything:
root@:  npm install -g rxjs-tslint
  npm install -g "tslint@^5.0.0"
  npm install -g "typescript@>=2.1.0"
rxjs-5-to-6-migrate -p src/tsconfig.app.json
)

ng update @angular/cli@7

maybe downgrade before:
  npm i @angular/animations@6.1.9

ng update @angular/common@7


https://update.angular.io/#7.2:8.0l2

ng update @angular/cli@8 @angular/core@8

Error: codelyzer blocks installation
  in package.json, replace ~ with ^ for it
  npm install codelyzer
ng update @angular/cli@8 @angular/core@8

ng update @angular/cdk@8
  The Angular CLI requires a minimum Node.js version of either v10.13 or v12.0.

according to https://linuxize.com/post/how-to-install-node-js-on-debian-10/
  curl -sL https://deb.nodesource.com/setup_12.x | sudo bash -
  ati nodejs
  npm install -g npm

npm install ng2-charts@latest