git-ubuntu 0.3 now building in the edge channel

[Nish Aravamudan]

Changes from 0.2.2 in the edge snap:

 - Fix LP: #1705542, to ensure that imported commits are not signed
(we don't have the uploaders' keys).

 - Fix LP: #1711174, which allows `git ubuntu lint` to verify that a
given bugfix is based off the correct branch.

 - Fix LP: #1718469, which fixes support for GIT_DIR.

 - Fix LP: #1718019, which ensures we only use Launchpad as a source
of publication data.

 - Fix LP: #1713530, which ensures we pass -v for Ubuntu merge builds.

 - Manpages are now available in the snap. To make them accessible
(for now), add

MANDATORY_MANPATH /snap/git-ubuntu/current/usr/share/man

to ~/.manpath. A future release will have, hopefully, a better mechanism.

- Fix LP: #1721128, which ensures we use the proper LXD image when
building, based upon the changelog distribution.

- Fix LP: #1721872, which ensures that debsign (gpg) is able to run
from within the snap.

- Fix LP: #1721899, which fixes `git ubuntu build` when not using LXD.