Instability in the automated tests sometimes would sometimes fail when
running "podman images --format {{.ID}}". It turns out that in versions
prior to podman 4.3.0, podman volumes (stored in
~/.local/share/contaiers) would get corrupted when multiple tests were
run in parallel.
The current solution is to wrap the test command to run sequentially in
versions prior to the fix and in parallel for versions after that.
Fixes#217
