remove signing

.github/workflows/docker-publish.yml

@@ -35,14 +35,6 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v3
 
-      # Install the cosign tool except on PR
-      # https://github.com/sigstore/cosign-installer
-      - name: Install cosign
-        if: github.event_name != 'pull_request'
-        uses: sigstore/cosign-installer@6e04d228eb30da1757ee4e1dd75a0ec73a653e06 #v3.1.1
-        with:
-          cosign-release: "v2.1.1"
-
       # Set up BuildKit Docker container builder to be able to build
       # multi-platform images and export cache
       # https://github.com/docker/setup-buildx-action