force install cython

Author: rflamary

.github/workflows/build_wheels.yml

@@ -26,7 +26,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install -r requirements.txt
-        
+        pip install -U "cython"
     - name: Install cibuildwheel
       run: |
         python -m pip install cibuildwheel==1.3.0