Add --dry-run option

[andresriancho]

OPTIONS
       --dry-run | --no-dry-run (boolean)
          Checks whether you have the required  permissions  for  the  action,
          without actually making the request, and provides an error response.
          If you have the required permissions, the error response is  DryRun-
          Operation . Otherwise, it is UnauthorizedOperation .

With this option the tool might run faster!

Enable it by default?