Currently, this pulls the postgresql installation when installing swh.core
which is not something wanted. That bypasses the current production pinning
done in puppet and installs the latest postgresql-13 for example.
That particular dependency should be installed alongside swh modules which
needs the core db pytest-plugin for their tests.
As impacts, i expect current packages needing this to break a bit but nothing
too serious nor difficult to fix. I'll adapt accordingly when/if this lands.