release_process: maybe clarify/reword what to pass to tails-iuk-generate-upgrade-description-files
For both 3.10(*) and 3.11 I’ve had some troubles deciding what to pass
tails-iuk-generate-upgrade-description-files call, probably because
I was a bit confused by the current notes.
It might be that a good rule of thumb would be to pass a
--previous-version for each version specified in the
IUK_SOURCE_VERSIONS variable, what do you think?