Update codecov/codecov-action action to v6 (#1559)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/ci.yaml

@@ -44,7 +44,7 @@ jobs:
       - name: Run tests
         run: tox run -e unit
       - name: Upload Coverage to Codecov
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@v6
         env:
           CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
     permissions: {}