message: fix(@nguniversal/common): combine path using `posix.join`
  This avoid having leading `/` when the left handside path is empty.
diff: @@ -32,6 +32,7 @@ import {
  } from '@schematics/angular/utility/dependencies';
  import { findBootstrapModulePath } from '@schematics/angular/utility/ng-ast-utils';
  import { getWorkspace, updateWorkspace } from '@schematics/angular/utility/workspace';
  +import { posix } from 'path';
  import * as ts from 'typescript';
  import { Schema as NgAddOptions } from './schema';
  @@ -123,8 +124,8 @@ function addScriptsRule(options: NgAddOptions): Rule {
  if (options.ssr) {
  pkg.scripts = {
  ...pkg.scripts,
  - 'build:client-and-server': `ng build ${options.clientProject} && ng build ${options.clientProject}:server`,
  - 'build:server': `ng build ${options.clientProject}:server`,
  + 'build:client-and-server': `ng build ${options.clientProject} && ng run ${options.clientProject}:server`,
  + 'build:server': `ng run ${options.clientProject}:server`,
  'serve:ssr': `node dist/${options.clientProject}/server/main.js`,
  };
  }
  @@ -142,8 +143,8 @@ function updateWorkspaceRule(options: NgAddOptions): Rule {
  builder: '@angular-devkit/build-angular:server',
  options: {
  outputPath: `dist/${options.clientProject}/server`,
  - main: `${project.sourceRoot}/server.ts`,
  - tsConfig: `${project.root}/tsconfig.server.json`,
  + main: posix.join(project.sourceRoot ?? '', 'server.ts'),
  + tsConfig: posix.join(project.root, 'tsconfig.server.json'),
  bundleDependencies: false,
  optimization: false,
  },
  