fix(ebrainslab): pin version of py-ipywidgets and py-jupyterlab-widgets

to be compatible with the Lab's base image

site-config/ebrainslab/spack.yaml

@@ -7,7 +7,7 @@ spack:
     - py-notebook
     - r-irkernel
     # "collab"-specific constraint to match ("jupyterlab_widgets") in the base image
-    - py-ipywidgets
+    - py-ipywidgets@7.7.0
+    - py-jupyterlab-widgets@1.1.0
     # Collab utils
     - clb-nb-utils@0.1.0
-