Workbench: Another stab at fixing PDM and its plugins.

I think that it was pdm-publish (that hasn't been updated for over 2
years) that's causing the issue. It requires an older version of PDM and
because of that it's breaking the installation of pdm-version and leaves
PDM broken (pipx downgrades PDM but the dependencies aren't installed
properly). Just a theory, let's check.