Fix JupyterLab 2 build

Author: martinRenou

.github/workflows/main.yml

@@ -99,7 +99,7 @@ jobs:
             jlab_version: 3
           - python: '3.9'
             dist: 'ipycanvas*.whl'
-            jlab_version: 2
+            jlab_version: 2.3.2
 
     steps:
 
@@ -128,8 +128,8 @@ jobs:
           pip install -vv ${{ matrix.dist }}
 
       - name: Manually install labextension for lab2
-        if: ${{ matrix.jlab_version }} == 2
-        run: jupyter labextension install .
+        if: ${{ matrix.jlab_version }} == 2.3.2
+        run: jupyter labextension install --debug .
 
       - name: Test installation files
         run: |