Default python version to loosely defined

[bernt-matthias]

This apparently leads to install python 3.13 which does not work in planemo test.

[nsoranzo]

Do you have a traceback to better understand what's going wrong?

[bernt-matthias]

I had a colleague who did hist first steps with planemo test. During startup a missin boltons package was reported.

From the used venv (I remember it was something like ~/.planemo/gx_venv_3.13/) I guessed that python 3.13 is used. And the printed pinnings suggested that boltons is not installed due to some restrictions in Galaxy's pinnings: https://github.com/galaxyproject/galaxy/blob/dda0e9b4e747b6a21d90f63c3d7c59e02ead8739/lib/galaxy/dependencies/pinned-requirements.txt#L34.