Axel Rau writes:
/usr/local/py_venv/mailman_33/lib/python3.9/site-packages/readme_renderer/markdown.py:44: UserWarning: Markdown renderers are not available. Install 'readme_renderer[md]' to enable Markdown rendering. warnings.warn(_EXTRA_WARNING)
I installed cmarkgfm 0.8.0 in my venv,
Why did you do that? Is it something in our documentation?
The error message is specifically asking for readme_renderer, which is a package available from PyPI. Try installing that. I'm not sure what the "[md]" means (the suffix "[md]" is also in postorius/setup.py), but it probably doesn't matter since readme_renderer.markdown is imported directly by Postorius. Just installing the package should make Postorius happy.
Note that something is not right because running setup.py in the venv should automatically install readme_renderer, and I would expect you may have other problems if setup.py did not work correctly.