chore(docs): bump Angular version to 8
chore(docs): bump Angular version to 8

BREAKING CHANGE: use Angular 8 (and related libs)

tomastrajan/angular-ngrx-material-starter,tomastrajan/angular-ngrx-material-starter,tomastrajan/angular-ngrx-material-starter,tomastrajan/angular-ngrx-material-starter