message: fix: don't include mocha types on no mocha
diff: @@ -467,12 +467,16 @@ class App extends Generator {
  'tslib@^1',
  )
  devDependencies.push(
  - '@types/chai@^4',
  - '@types/mocha@^5',
  '@types/node@^10',
  'typescript@^3.3',
  'ts-node@^8',
  )
  + if (this.mocha) {
  + devDependencies.push(
  + '@types/chai@^4',
  + '@types/mocha@^5',
  + )
  + }
  if (this.tslint) {
  devDependencies.push(
  '@oclif/tslint@^3',
  