Workbench: remove pdm-version.

Just let it end.

workbench/Dockerfile

@@ -232,8 +232,8 @@ RUN apt-get update && \
     && \
     pipx install chalice && \
     pipx install curator-opensearch && \
-    pipx install pdm && \
-    pipx inject pdm pdm-packer pdm-version && \
+    pipx install 'pdm>=2' && \
+    pipx inject pdm pdm-packer && \
     npm install --global \
         corepack \
         @playwright/test \