do not bother with codecov.io, it's unreliable

.github/workflows/test.yml

@@ -52,15 +52,6 @@ jobs:
     - name: Test
       run: make coverage PYTHON=python
 
-    - name: Upload Coverage to Codecov
-      if: always()
-      uses: codecov/codecov-action@v3
-      env:
-        PYTHON: ${{ matrix.python-version }}
-      with:
-        env_vars: PYTHON
-        fail_ci_if_error: true
-
     - name: Upload Coverage as artifact
       if: always()
       uses: actions/upload-artifact@v3