fix: use custom image having tox already installed

This MR reduces pull usage and CI load by using an image already in our registry with tox installed.

I use a rather big image: registry.logilab.fr/logilab/infra/dockerfiles/debian-buster-slim-pg11

kinda related https://forge.extranet.logilab.fr/logilab/infra/dockerfiles/-/merge_requests/32 a MR to reduce the image size.

May be we should use : https://forge.extranet.logilab.fr/cubicweb/dockerfiles for a smaller image

Actually we want images from this repository since the one merged here is private and will break on all the CI cluster :/

We also have both a pg11 image for py3 jobs and a python-logilab (with tox) for linting jobs so we need to fix this pretty soon otherwise the CI will be half broken :/ (I'll take a look tomorrow)

Thank you @bram if you can have a look into this. (Yes… it breaks half of the CI :) )

marked this merge request as ready

requested review from @fferry

approved this merge request

added 3 commits

• c61ac735...89645cef - 2 commits from branch branch/default
• 5b9b56558d87 - fix: use custom image having tox already installed

Compare with previous version

merged