As discussed in the architecture call on 23 Jan
(https://docs.google.com/document/d/1irGxNEanKL-d-KAySsWJNiJZJuEV3EOYnzTXIQ4CDBg/edit#heading=h.4hx4r3c602yg),
we do not want to test package-to-package upgrades in CI because we have
no way of changing the content of the packages and if the tests start
failing we will be unable to make the jobs pass.