Bump codecov/codecov-action from 3 to 4 (#401)

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Sam Bull <git@sambull.org>

.github/workflows/ci-cd.yml

@@ -92,9 +92,10 @@ jobs:
         COLOR: 'yes'
     - run: python -m coverage xml
     - name: Upload coverage
-      uses: codecov/codecov-action@v3
+      uses: codecov/codecov-action@v4
       with:
         fail_ci_if_error: true
+        token: ${{ secrets.CODECOV_TOKEN }}
 
   check:  # This job does nothing and is only used for the branch protection
     if: always()