chore(deps): update sigstore/cosign-installer action to v3.9.1

Author: renovate[bot]

.github/workflows/docker-publish.yml

@@ -39,7 +39,7 @@ jobs:
       # https://github.com/sigstore/cosign-installer
       - name: Install cosign
         if: github.event_name != 'pull_request'
-        uses: sigstore/cosign-installer@v3.8.2
+        uses: sigstore/cosign-installer@v3.9.1
 
       # Workaround: https://github.com/docker/build-push-action/issues/461
       - name: Setup Docker buildx