updated codecov CI action

- use v4
- use CODECOV_TOKEN (added to GH)
- renamed step from CodeCov to codecov
- add verbose flag

.github/workflows/CI.yaml

@@ -66,15 +66,17 @@ jobs:
       run: |
         pytest -v --cov=membrane_curvature --cov-report=xml --color=yes membrane_curvature/tests/
 
-    - name: CodeCov
+    - name: codecov
       if: ${{ github.repository == 'MDAnalysis/membrane-curvature'
               && github.event_name == 'pull_request' }}
-      uses: codecov/codecov-action@v3
+      uses: codecov/codecov-action@v4
       with:
+        token: ${{ secrets.CODECOV_TOKEN }}
         file: ./coverage.xml
         flags: unittests
         name: codecov-${{ matrix.os }}-py${{ matrix.python-version }}
         fail_ci_if_error: True
+        verbose: True
 
   upstream_develop:
     runs-on: ubuntu-latest