Externally managed version on Activity base class #42
Description
It will be useful to store an externally managed version on the activity class - i.e. one that is independent of the document version.
For example, in CMIP6 it is useful to periodically release a version of a MIP document, for which perhaps only some Contained experiments have been updated. The user in this case is concerned about the version at the MIP level.
This could be done with an external_version property on the Activity class, or similar?