Not requiring SRU changes to be in $current-stable to go in the LTS

[Sebastien Bacher]

(I'm not sure what's the best place to discuss the SRU process but it 
has been suggested that this list might be appropriate so I'm starting here)

Good afternoon,

 From my experience, it's common practice from the SRU team to require 
for a bug to be fixed in $current-stable to be SRUed to the LTS (e.g to 
need a cosmic SRU first to be able to have a SRU for bionic).

I would like to ask if we could revisit that requirement, which I 
believe is resource expensive and bring us little benefit.

Some arguments
- our team members are usually either using the current devel version or 
the current LTS, which means in practice the current-stable SRUs get 
tested in a VM or not tested at all before upload
- we often get no feedback at all on the nonLTS version of the SRU, 
those tend to sit longer in proposed by lack of verification
- the previous items leads us to often validate the LTS update before 
the non LTS one so we can't really argue that the nonLTS upload helps to 
get more testing and reduce risks on the LTS one
- the non LTS/newer series are often less polished so we can't really 
argue that users upgrading from e.g bionic to cosmic shouldn't be 
exposed to problems that were resolved while they were on the LTS
- it makes sense to put the extra polish effort for a LTS serie
- we should trust the maintainer's judgement, often it makes sense to 
fix important issues in current-stable, especially after release, but as 
we get closer from the next stable those SRU makes less sense

Reading the wiki documentation 
(https://wiki.ubuntu.com/StableReleaseUpdates) it seems the only 
documented requirement is to fix the issue in the devel version first?

Cheers,
Sebastien Bacher