Update docker-publish.yml

Author: rursache

.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@f3c664df7af409cb4873aa5068053ba9d61a57b6 #v2.6.0
+        uses: sigstore/cosign-installer@9becc617647dfa20ae7b1151972e9b3a2c338a2b #v2.8.1
         with:
           cosign-release: 'v1.13.1'