message: fix: always use --save with npm
  this forces saving to package.json even if save=false is set in npmrc
diff: @@ -480,9 +480,10 @@ class App extends Generator {
  if (process.env.YARN_MUTEX) yarnOpts.mutex = process.env.YARN_MUTEX
  const install = (deps: string[], opts: object) => this.yarn ? this.yarnInstall(deps, opts) : this.npmInstall(deps, opts)
  const dev = this.yarn ? {dev: true} : {'save-dev': true}
  + const save = this.yarn ? {} : {save: true}
  Promise.all([
  install(devDependencies, {...yarnOpts, ...dev, ignoreScripts: true}),
  - install(dependencies, yarnOpts),
  + install(dependencies, {...yarnOpts, ...save}),
  ]).then(() => {
  if (['plugin', 'multi'].includes(this.type)) {
  this.spawnCommandSync(path.join('.', 'node_modules/.bin/oclif-dev'), ['readme'])
  