google-cloud-python: design a migration away from defaultVersion #4772
Description
Currently we specify a default version in repo metadata, and this is used by the post-processor. Changing the default version is effectively a breaking change, so this isn't something we want to happen implicitly in any generated library, as otherwise adding a new API path might do the wrong thing.
This makes it effectively a required field though, and we'd prefer not to have that - it will make API onboarding for Python more toilsome than for other languages, for example.
We should think carefully about whether we can remove this concept entirely - potentially over the course of a long time.