[Merge] lp:~marcustomlinson/update-manager/update-manager into lp:update-manager

[Iain Lane]

Free-form thoughts

  - This causes polkit prompts from snapd, is that acceptable?
  - I'm not sure that putting it after apt updating and before apt installing is right - what if we:
    - update ubuntu-release-upgrader-core (new transitions to know about)
    - Change the seeds (things get marked as removable that weren't before)
    ?
  - Why is there a spawned thread and how is it supposed to be waited on? (Could be fine, I just can't tell)
  - Would probably be better to use snapd-glib

I'll probably follow up with more later!
-- 
https://code.launchpad.net/~marcustomlinson/update-manager/update-manager/+merge/380060
Your team Ubuntu Core Development Team is requested to review the proposed merge of lp:~marcustomlinson/update-manager/update-manager into lp:update-manager.