fixed codecov?

.github/workflows/python-package.yml

@@ -112,7 +112,7 @@ jobs:
       run: |
         python -m pip install wheel
         python -m pip install --upgrade pip
-        python -m pip install flake8 pytest pytest-cov
+        python -m pip install flake8 pytest pytest-cov cython
         python setup.py build_ext --inplace
         # pip install -r requirements.txt
     - name: Install CAJAL