'ng update' does not work with yarn workspaces

Start with the update command implementation linked at packages/angular/cli/commands/update-impl.ts around line 123, then reproduce the failure using a Yarn workspace with Angular dependencies only in workspace-a/package.json. Verify how dependency resolution behaves from the workspace directory; done means ng update finds and can update the workspace's Angular dependencies without requiring them in the root package.json.

🐞 Bug report

Command (mark with an x)

- [ ] new
- [ ] build
- [ ] serve
- [ ] test
- [ ] e2e
- [ ] generate
- [ ] add
- [X] update
- [ ] lint
- [ ] xi18n
- [ ] run
- [ ] config
- [ ] help
- [ ] version
- [ ] doc

Is this a regression?

No

Description

I am utilizing yarn workspaces -feature in my project. Problem is that I have to keep Angular & AngularCLI dependencies on root packages.json, otherwise 'ng update' command can't figure out the version I currently have. I'd rather keep root package.json clean and move Angular & CLI dependencies to project/package.json to keep things isolated.

Looking at the code, update command resolves dependencies from root package, even when command is executed on package folder. Would it be possible to change behavior in a way that update would first check package dependencies and the fall back to root if nothing is found?

🔬 Minimal Reproduction

• init yarn workspace project as follows: https://yarnpkg.com/lang/en/docs/workspaces/
• init angular app with cli and move dependencies from root package.json to workspace-a/package.json (example from previous step)
• wait until new angular version is available
• cd to 'workspace-a' and run 'ng update'. Command fails to find any dependencies to update.

🔥 Exception or Error

N/A

🌍 Your Environment

Angular CLI: 8.0.3
Node: 10.15.3
OS: win32 x64
Angular: 8.0.1
... animations, common, compiler, compiler-cli, core, forms
... language-service, platform-browser, platform-browser-dynamic
... router, service-worker

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.800.3
@angular-devkit/build-angular     0.800.3
@angular-devkit/build-optimizer   0.800.3
@angular-devkit/build-webpack     0.800.3
@angular-devkit/core              8.0.3
@angular-devkit/schematics        8.0.3
@angular/cli                      8.0.3
@angular/pwa                      0.800.3
@ngtools/webpack                  8.0.3
@schematics/angular               8.0.3
@schematics/update                0.800.3
rxjs                              6.4.0
typescript                        3.4.5
webpack                           4.30.0

Root package.json:

  "dependencies": {},
  "devDependencies": {
    "npm-run-all": "^4.1.5"
  },

'workspace-a/package.json':

"dependencies": {
    "@angular/animations": "~8.0.1",
    "@angular/common": "~8.0.1",
    "@angular/compiler": "~8.0.1",
    "@angular/core": "~8.0.1",
    "@angular/forms": "~8.0.1",
    "@angular/platform-browser": "~8.0.1",
    "@angular/platform-browser-dynamic": "~8.0.1",
    "@angular/pwa": "^0.800.3",
    "@angular/router": "~8.0.1",
    "@angular/service-worker": "~8.0.1",
    "@auth0/angular-jwt": "^2.1.0",
    "@ngx-translate/core": "^11.0.1",
    ...
    "rxjs": "~6.4.0",
    "tslib": "^1.9.0",
    "zone.js": "~0.9.1"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "~0.800.0",
    "@angular/cli": "~8.0.3",
    "@angular/compiler-cli": "~8.0.1",
    "@angular/language-service": "~8.0.1",
    ...
  }

Anything else relevant?