Extend CI coverage to test upgrade

Currently, Sylva CI tests "only" fresh install. Starting from v1.0, we'll commit to support upgrade. We should start expanding our CI framework to allow testing of upgrade from a given version to a target version.

Until we support upgrade post v1.0, we should use that framework to start experimenting upgrades in CI on a regular basis: e.g. from preivous day main branch to current status of main branch. (there would be no value to test upgrade from v0.2 to daily update of main branch as we know we included change that would require dedicated work to support upgrade and we won't support that in 1.0

cc @loic.nicolle @matrohon @tmmorin @feleouet @rletrocquer @baburciu @cristian.manda