Add constraint for older py-ipywidgets

In the collab base image there's jupyterlab-widgets@1.0.2 (installed via pip), which seems incompatible with ipywidgets@8.0.2 (in the current experimental deployment) → let's add a version constraint for ipywidgets to stay in the 7.7 range (7.7.0 worked before, current stable).

This is a site-specific change that should go into the site/collab thingy…

I'm not 100% sure this will work, from what I can see the (Spack) jupyterlab-widgets version is still the same as before (3.0.3, when in the Lab it's 1.0.2) :/

==> Concretized py-ipycanvas
 -   qi53hrh  py-ipycanvas@0.12.0%gcc@10.3.0 build_system=python_pip arch=linux-ubuntu20.04-x86_64
 -   cf3djcr      ^py-ipywidgets@7.7.0%gcc@10.3.0 build_system=python_pip arch=linux-ubuntu20.04-x86_64
[^]  qcbi23k          ^py-ipykernel@6.16.0%gcc@10.3.0 build_system=python_pip arch=linux-ubuntu20.04-x86_64
[^]  alq6jax          ^py-ipython@8.5.0%gcc@10.3.0 build_system=python_pip arch=linux-ubuntu20.04-x86_64
[^]  a3prdrh          ^py-ipython-genutils@0.2.0%gcc@10.3.0 build_system=python_pip arch=linux-ubuntu20.04-x86_64
[^]  tzljynt          ^py-jupyterlab-widgets@3.0.3%gcc@10.3.0 build_system=python_pip arch=linux-ubuntu20.04-x86_64
[^]  dsa5znr          ^py-nbformat@5.4.0%gcc@10.3.0 build_system=python_pip arch=linux-ubuntu20.04-x86_64
[^]  4x64oxz          ^py-traitlets@5.3.0%gcc@10.3.0 build_system=python_pip arch=linux-ubuntu20.04-x86_64
 -   56kdrch          ^py-widgetsnbextension@3.6.0%gcc@10.3.0 build_system=python_pip arch=linux-ubuntu20.04-x86_64
[^]  duln7yo              ^py-notebook@6.4.12%gcc@10.3.0 build_system=python_pip arch=linux-ubuntu20.04-x86_64
...

Maybe constrain that too?

mentioned in commit 29cff6e9

merged

I was wrong, it looks fine (I think?)

Could you quickly check in the lab-int (EBRAINS-test kernel) and let me know if it's OK?

I'll update the experimental tonight :)

Thx, it works!