When pip is upgraded to 20.3, the pip dependency resolver is much more
strict and will no longer install a combination of packages that is mutually
inconsistent[0].
These changes account for the fact that Shipyard imports Armada, Drydock,
Promenade, and Deckhand. Having said that, with pip 20.3, the pip
packages amongst those projects cannot conflict. A follow-up change may
be needed if more conflicts are found.
[0] https://pip.pypa.io/en/latest/user_guide/#changes-to-the-pip-dependency-resolver-in-20-2-2020
Change-Id: Id75acea82ddf5d915a8b8805e076dac49cab800f
1f0c011a17