Update quickstart.sh (#589)
Update quickstart.sh (#589)

SDKGenerator expects the Xplatcoretemplate to be a specific folder name (xplatcppsdk). So changing the quickstart to reflect this.

This doesn't affect any build issue, just local development.
PlayFab/SDKGenerator,PlayFab/SDKGenerator,PlayFab/SDKGenerator,PlayFab/SDKGenerator,PlayFab/SDKGenerator,PlayFab/SDKGenerator,PlayFab/SDKGenerator,PlayFab/SDKGenerator,PlayFab/SDKGenerator