eu tenhotravis-ci integrado à minha conta GitHub (https://github.com/pradeep0601/Angular5-Router-App)

Quando eu atualizei@angular/cli versão 1.7.4 a 6.0.0-rc.3, a construção começou a falhar com um erro:

Local workspace file ('angular.json') could not be found.
Error: Local workspace file ('angular.json') could not be found.
    at WorkspaceLoader._getProjectWorkspaceFilePath (/home/travis/build/pradeep0601/Angular5-Router-App/node_modules/@angular/cli/models/workspace-loader.js:37:19)
    at WorkspaceLoader.loadWorkspace (/home/travis/build/pradeep0601/Angular5-Router-App/node_modules/@angular/cli/models/workspace-loader.js:24:21)
    at TestCommand._loadWorkspaceAndArchitect (/home/travis/build/pradeep0601/Angular5-Router-App/node_modules/@angular/cli/models/architect-command.js:177:32)
    at TestCommand.<anonymous> (/home/travis/build/pradeep0601/Angular5-Router-App/node_modules/@angular/cli/models/architect-command.js:45:25)
    at Generator.next (<anonymous>)
    at /home/travis/build/pradeep0601/Angular5-Router-App/node_modules/@angular/cli/models/architect-command.js:7:71
    at new Promise (<anonymous>)
    at __awaiter (/home/travis/build/pradeep0601/Angular5-Router-App/node_modules/@angular/cli/models/architect-command.js:3:12)
    at TestCommand.initialize (/home/travis/build/pradeep0601/Angular5-Router-App/node_modules/@angular/cli/models/architect-command.js:44:16)
    at /home/travis/build/pradeep0601/Angular5-Router-App/node_modules/@angular/cli/models/command-runner.js:100:23

snippet package.json para entender melhor o ambiente em execução:

    "@angular/cli": "6.0.0-rc.3",
    "@angular/compiler-cli": "^5.2.0",
    "@angular/language-service": "^5.2.0",
    "@types/jasmine": "~2.8.3",
    "@types/jasminewd2": "~2.0.2",