[Discovery] Do we need an optional "version" attribute?
Would it be helpful to clients to know the version string associated with a service? It would be optional and for informational purposes only. I don't think the spec should mandate any semantics meaning or format to it. But it might be useful if there was a common spot for UIs to get this info to display to their users - in particular, if they wanted to search the web for more info on that version of the Service (even though we have a docs URL) in the schema.
Note this is about a version string for the Service itself, not the Service Entry in the Discovery Endpoint. For the Service Entry, see #691
Closing since the latest version of the Registry spec includes a "version" attribute.