Fix mokito version

.github/workflows/test.yaml

@@ -24,7 +24,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install pytest mockito pytest-cov codecov
+          pip install pytest mockito==1.4.0 pytest-cov codecov
           pip install -r requirements.txt
       - name: Run tests
         run: |