{
  "name": "ngx-progressbar",
  "version": "6.0.1",
  "peerDependencies": {
    "@angular/common": "^8.0.0",
    "@angular/core": "^8.0.0",
    "@angular/router": "^8.0.0",
    "rxjs": "^6.0.0"
  }
}

{
  "name": "ngx-progressbar",
  "version": "6.0.1",
  "peerDependencies": {
    "@angular/common": ">=8.0.0",
    "@angular/core": ">=8.0.0",
    "@angular/router": ">=8.0.0",
    "rxjs": ">=6.0.0"
  }
}

Remove the install warning in angular version 9
Remove the install warning in angular version 9