Could not find the implementation for builder @angular-devkit/build-angular:dev-server on ng serve command

I tried to update the angular CLI following this, but now I can’t run my app. When I try to run the command ng serve, it gives me this error:

Could not find the implementation for builder @angular-devkit/build-angular:dev-server
Error: Could not find the implementation for builder @angular-devkit/build-angular:dev-server
    at WorkspaceNodeModulesArchitectHost.resolveBuilder (C:\Users\Lupus\Documents\full-stack-projects\financial-app-ui\node_modules\@angular\cli\node_modules\@angular-devkit\architect\node\node-modules-architect-host.js:49:19)
    at ServeCommand.initialize (C:\Users\Lupus\Documents\full-stack-projects\financial-app-ui\node_modules\@angular\cli\models\architect-command.js:135:55)
    at process._tickCallback (internal/process/next_tick.js:68:7)
    at Function.Module.runMain (internal/modules/cjs/loader.js:745:11)
    at startup (internal/bootstrap/node.js:283:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:743:3)

I have tried everything I could found.

• I tried to manually install devkit with the command npm install --save-dev @angular-devkit/build-angular
• I tried to run the command npm i --only=dev
• I tried to run the commands

:

npm install
ng update
npm update

• Removed the node_modules folder and the package-lock.json file and ran the commands all again.

Nothing worked. Running ng v gives me this:

Angular CLI: 8.0.3
Node: 10.15.0
OS: win32 x64
Angular: 8.0.1
... animations, cdk, common, compiler, compiler-cli, core, forms
... language-service, platform-browser, platform-browser-dynamic
... router

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.13.9
@angular-devkit/build-angular     0.13.9
@angular-devkit/build-optimizer   0.13.9
@angular-devkit/build-webpack     0.13.9
@angular-devkit/core              7.3.9
@angular-devkit/schematics        8.0.3
@angular/cli                      8.0.3
@ngtools/webpack                  7.3.9
@schematics/angular               8.0.3
@schematics/update                0.800.3
rxjs                              6.5.2
typescript                        3.4.5
webpack                           4.29.0

And my package.json is like this:

{
  "name": "financial-app-ui",
  "version": "0.0.0",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "^8.0.1",
    "@angular/cdk": "^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/router": "^8.0.1",
    "core-js": "^2.6.9",
    "font-awesome": "^4.7.0",
    "primeicons": "^1.0.0",
    "primeng": "^7.1.3",
    "rxjs": "~6.5.2",
    "tslib": "^1.10.0",
    "zone.js": "~0.9.1"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "^0.13.9",
    "@angular/cli": "^8.0.3",
    "@angular/compiler-cli": "^8.0.1",
    "@angular/language-service": "^8.0.1",
    "@types/jasmine": "~2.8.8",
    "@types/jasminewd2": "~2.0.3",
    "@types/node": "~8.9.4",
    "codelyzer": "~4.5.0",
    "jasmine-core": "~2.99.1",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~4.0.0",
    "karma-chrome-launcher": "~2.2.0",
    "karma-coverage-istanbul-reporter": "~2.0.1",
    "karma-jasmine": "~1.1.2",
    "karma-jasmine-html-reporter": "^0.2.2",
    "protractor": "~5.4.0",
    "ts-node": "~7.0.0",
    "tslint": "~5.11.0",
    "typescript": "~3.4.5"
  }
}

Does anyone have any other suggestion?