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

| datasource  | package                | from   | to |
| ----------- | ---------------------- | ------ | -- |
| github-tags | codecov/codecov-action | v5.5.4 | v6 |


Signed-off-by: renovate-sh-app[bot] <219655108+renovate-sh-app[bot]@users.noreply.github.com>

Author: renovate-sh-app[bot]

.github/workflows/test.yml

@@ -45,7 +45,7 @@ jobs:
         run: go test -count 1 -coverprofile=coverage.txt ./...
       - name: Upload Coverage
         if: ${{ matrix.platform == 'ubuntu-latest' && github.ref_name == 'main' }}
-        uses: codecov/codecov-action@75cd11691c0faa626561e295848008c8a7dddffe # v5.5.4
+        uses: codecov/codecov-action@57e3a136b779b570ffcdbf80b3bdc90e7fab3de2 # v6
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           slug: grafana/k6deps