message: fix readme.md to include 2016/06/01 with 2018/03/01 always
diff: @@ -42,6 +42,9 @@ These settings apply only when `--tag=package-2018-03-preview` is specified on t
  ``` yaml $(tag) == 'package-2018-03-preview'
  input-file:
  - Microsoft.Subscription/preview/2018-03-01-preview/subscriptions.json
  +- Microsoft.Subscription/stable/2016-06-01/subscriptions.json
  +title: SubscriptionClient
  +description: The subscription client
  ```
  ### Tag: package-2017-11-preview
  