Pin matplotlib version for Windows CI (#861)

.github/workflows/windows.yml

@@ -66,6 +66,7 @@ jobs:
 
             - name: Install dependencies
               run: |
+                  pip install matplotlib==3.9.0
                   pip install -r requirements.txt
                   pip install .
                   pip install pytest
@@ -78,4 +79,4 @@ jobs:
 
             - name: Testing with pytest
               run: |
-                 pytest . --verbose
+                  pytest . --verbose