message: Fix bad package name for storagecache in go sdk
diff: @@ -15,5 +15,5 @@ These settings apply only when `--tag=package-2019-08 --go` is specified on the
  Please also specify `--go-sdks-folder=<path to the root directory of your azure-sdk-for-go clone>`.
  ```yaml $(tag) == 'package-2019-08' && $(go)
  -output-folder: $(go-sdk-folder)/services/preview/$(namespace)/mgmt/2019-08/$(namespace)
  +output-folder: $(go-sdk-folder)/services/preview/$(namespace)/mgmt/2019-08-01-preview/$(namespace)
  ```
  