Include transitions in the feature freeze definition

[Sebastien Bacher]

Hey ubuntu release!

Reading https://wiki.ubuntu.com/FeatureFreeze it doesn't seem to cover
packaging changes, but renaming a binary can have an high impact on the
archive.  I'm proposing that we add 'starting a transition' as something
that requires a ffe.


Why?

The practical situation that made me check the definition is
https://bugs.launchpad.net/ubuntu/+source/libffi/+bug/1943288. The
libffi soname means that some days before beta we are having

- lot of rebuilds which are keeping the builders busy and creating delays
- packages blocked in proposed for over a week, beta freeze is monday
(which means tomorrow if we don't count on people working during the
weekend)
-  our fixes and improvement not landing on the daily ISO and tested
before beta

This is going to have a negative impact on our beta quality, I think the
freezes should protect us against those disturbances.

(the libffi update might be covered by the current rules so let's not
discuss that particular case. We could take a poppler update as an
example instead since upstream bumps the soname at every new version
even if those include no API changes and only bugfixes)


Thanks for considering,
Sebastien Bacher