Thanks Erick.
We do have toolkits for specific code languages which you can find here:
Rally Software Tools · GitHub
However, it sounds like it's not what you need. We don't have a converter between our WSAPI endpoints and OpenAPI.
It does sound like a good enhancement request which you are welcome to post to the Ideas site at: https://ideas.rallydev.com
If you are able to convert manually then it sounds like it should be possible to create a program or utility to do that, hopefully it can be implemented.
It sounds like you are converting all endpoints. Why are you asking only about the Workspace endpoint?
I included the references to the toolkits only for that perhaps you can find more on Workspace there which may help you with converting.
Let us know.
Sagi