[upd] github-actions: Bump docker/scout-action from 1.20.4 to 1.21.0

Bumps [docker/scout-action](https://github.com/docker/scout-action) from 1.20.4 to 1.21.0.
- [Release notes](https://github.com/docker/scout-action/releases)
- [Commits](https://github.com/docker/scout-action/compare/bacf462e8d090c09660de30a6ccc718035f961e3...cd72f264beff1cd72735de31148b9d3244a0234a)

---
updated-dependencies:
- dependency-name: docker/scout-action
  dependency-version: 1.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/security.yml

@@ -29,7 +29,7 @@ jobs:
           persist-credentials: "false"
 
       - name: Sync GHCS from Docker Scout
-        uses: docker/scout-action@bacf462e8d090c09660de30a6ccc718035f961e3  # v1.20.4
+        uses: docker/scout-action@cd72f264beff1cd72735de31148b9d3244a0234a  # v1.21.0
         with:
           organization: "searxng"
           dockerhub-user: "${{ secrets.DOCKER_USER }}"