chore(deps): update codecov/codecov-action action to v6

Author: renovate[bot]

.github/workflows/ci.yml

@@ -58,7 +58,7 @@ jobs:
         shell: bash
       - run: uv run pytest
         shell: bash
-      - uses: codecov/codecov-action@v5
+      - uses: codecov/codecov-action@v6
         with:
           token: ${{ secrets.CODECOV_TOKEN }}