Code review comment for lp:~malizor/update-manager/ppa-changelogs

I would honestly just depend on python3-launchpadlib. Yes, we don't have anything in the desktop requiring it right now, but that isn't a strong reason not to add it; and without it, most people will continue not to see PPA changelogs, which seems more compelling to me.

Other than that, this seems like a good start and the use of the LP API seems mostly right, but there are a few details to fix up. Thanks!