如何修复架构验证失败，出现以下错误：ng服务后

Question

在将Bootstrap安装到项目中后进行服务时遇到以下问题

Schema validation failed with the following errors:
  Data path ".builders['app-shell']" should have required property 'class'.
Error: Schema validation failed with the following errors:
  Data path ".builders['app-shell']" should have required property 'class'.
    at MergeMapSubscriber._registry.compile.pipe.operators_1.concatMap.validatorResult [as project] (C:\akshar\spectroo\node_modules\@angular-devkit\core\src\workspace\workspace.js:215:42)
    at MergeMapSubscriber._tryNext (C:\akshar\spectroo\node_modules\rxjs\internal\operators\mergeMap.js:69:27)
    at MergeMapSubscriber._next (C:\akshar\spectroo\node_modules\rxjs\internal\operators\mergeMap.js:59:18)
    at MergeMapSubscriber.Subscriber.next (C:\akshar\spectroo\node_modules\rxjs\internal\Subscriber.js:67:18)
    at MergeMapSubscriber.notifyNext (C:\akshar\spectroo\node_modules\rxjs\internal\operators\mergeMap.js:92:26)
    at InnerSubscriber._next (C:\akshar\spectroo\node_modules\rxjs\internal\InnerSubscriber.js:28:21)
    at InnerSubscriber.Subscriber.next (C:\akshar\spectroo\node_modules\rxjs\internal\Subscriber.js:67:18)
    at MapSubscriber._next (C:\akshar\spectroo\node_modules\rxjs\internal\operators\map.js:55:26)
    at MapSubscriber.Subscriber.next (C:\akshar\spectroo\node_modules\rxjs\internal\Subscriber.js:67:18)
    at SwitchMapSubscriber.notifyNext (C:\akshar\spectroo\node_modules\rxjs\internal\operators\switchMap.js:86:26)

{
  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
  "version": 1,
  "newProjectRoot": "projects",
  "projects": {
    "spectroo": {
      "root": "",
      "sourceRoot": "src",
      "projectType": "application",
      "prefix": "app",
      "schematics": {},
      "architect": {
        "build": {
          "builder": "@angular-devkit/build-angular:browser",
          "options": {
            "outputPath": "dist/spectroo",
            "index": "src/index.html",
            "main": "src/main.ts",
            "polyfills": "src/polyfills.ts",
            "tsConfig": "src/tsconfig.app.json",
            "assets": [
              "src/favicon.ico",
              "src/assets"
            ],
            "styles": [
              "node_modules/bootstrap/dist/css/bootstrap.min.css",
              "src/styles.css"
            ],
            "scripts": []
          },
          "configurations": {
            "production": {
              "fileReplacements": [
                {
                  "replace": "src/environments/environment.ts",
                  "with": "src/environments/environment.prod.ts"
                }
              ],
              "optimization": true,
              "outputHashing": "all",
              "sourceMap": false,
              "extractCss": true,
              "namedChunks": false,
              "aot": true,
              "extractLicenses": true,
              "vendorChunk": false,
              "buildOptimizer": true,
              "budgets": [
                {
                  "type": "initial",
                  "maximumWarning": "2mb",
                  "maximumError": "5mb"
                }
              ]
            }
          }
        },
        "serve": {
          "builder": "@angular-devkit/build-angular:dev-server",
          "options": {
            "browserTarget": "spectroo:build"
          },
          "configurations": {
            "production": {
              "browserTarget": "spectroo:build:production"
            }
          }
        },
        "extract-i18n": {
          "builder": "@angular-devkit/build-angular:extract-i18n",
          "options": {
            "browserTarget": "spectroo:build"
          }
        },
        "test": {
          "builder": "@angular-devkit/build-angular:karma",
          "options": {
            "main": "src/test.ts",
            "polyfills": "src/polyfills.ts",
            "tsConfig": "src/tsconfig.spec.json",
            "karmaConfig": "src/karma.conf.js",
            "styles": [
              "src/styles.css"
            ],
            "scripts": [],
            "assets": [
              "src/favicon.ico",
              "src/assets"
            ]
          }
        },
        "lint": {
          "builder": "@angular-devkit/build-angular:tslint",
          "options": {
            "tsConfig": [
              "src/tsconfig.app.json",
              "src/tsconfig.spec.json"
            ],
            "exclude": [
              "**/node_modules/**"
            ]
          }
        }
      }
    },
    "spectroo-e2e": {
      "root": "e2e/",
      "projectType": "application",
      "prefix": "",
      "architect": {
        "e2e": {
          "builder": "@angular-devkit/build-angular:protractor",
          "options": {
            "protractorConfig": "e2e/protractor.conf.js",
            "devServerTarget": "spectroo:serve"
          },
          "configurations": {
            "production": {
              "devServerTarget": "spectroo:serve:production"
            }
          }
        },
        "lint": {
          "builder": "@angular-devkit/build-angular:tslint",
          "options": {
            "tsConfig": "e2e/tsconfig.e2e.json",
            "exclude": [
              "**/node_modules/**"
            ]
          }
        }
      }
    }
  },
  "defaultProject": "spectroo"
}