message: Fix wrong preview pacakge path
diff: @@ -33,7 +33,7 @@ These settings apply only when `--tag=package-2019-08-preview --go` is specified
  Please also specify `--go-sdk-folder=<path to the root directory of your azure-sdk-for-go clone>`.
  ``` yaml $(tag) == 'package-2019-08-preview' && $(go)
  -output-folder: $(go-sdk-folder)/services/cosmos-db/mgmt/2019-08-01-preview/$(namespace)
  +output-folder: $(go-sdk-folder)/services/preview/cosmos-db/mgmt/2019-08-01-preview/$(namespace)
  ```
  ### Tag: package-2015-04 and go
  