fix: constrain py-matplotlib version

site-config/ebrainslab/packages.yaml

@@ -9,6 +9,9 @@ packages:
     r:
         # EM: +X fixes build for collab
         require: "@4.3.3+X"
+    py-matplotlib:
+        # EM: %matplotlib inline doesn't work for >=3.9
+        require: "@:3.8"
     py-torch:
         # ECM: No cuda nor rocm in collab VMs.
         #      I did not try to minimize the specification any further.