Fix Python version in build.json

[danielhollas]

This was an omission in #318. The Python version specified in build.json is used to automatically generate the image tags on Dockerhub. So currently, for example the image aiidalab/full-stack:python-9.4 actually corresponds to python-9.13

https://hub.docker.com/r/aiidalab/full-stack/tags

In short, when updating the Python version, we need to update both the stack/base/Dockerfile and build.json

[unkcpz]

Thanks! @danielhollas Last change #318 as you said is an omission.

I think the default BASE in stack/base/Dockerfile is set in docker-bake.hcl for build the image. Remove the ARG BASE=jupyter/minimal-notebook:python-3.9.13 should be fine and good to have only one place to set the version.

[unkcpz]

If seems the variable can not pass directly to FROM, but need to ARG first, https://stackoverflow.com/questions/36556766/can-a-variable-be-used-in-docker-from this may help.

[unkcpz]

Looks all good! Thanks!

[danielhollas]

@unkcpz thanks! I just confirmed that the images published before this PR were still on Python 9.4, so the PR in #318 didn't work.
The fix with ARG BASE was the same as what Marnik did in #311 for AIIDA_VERSION.

I'll open a new PR where I will do the same fix for AIIDALAB_VERSION and AIIDALAB_HOME_VERSION in stack/lab/Dockerfile.