how to upgrade the angular version in ionic project code example
Example: how to update angular core in ionic
npm i @ionic/angular@latest
npm i zone.js@~0.9.1
npm i @angular/core@"~8.x.x"
npm i @ionic/angular-toolkit@latest
npm i codelyzer@latest
npm remove @angular/http
ng update @angular/core @angular/cli --allow-dirty