Remove cosign steps from docker-publish.yml

Removed cosign installation and signing steps from Docker publish workflow.

Author: CybotTM

.github/workflows/docker-publish.yml

@@ -38,12 +38,6 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v2
 
-      # 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@1e95c1de343b5b0c23352d6417ee3e48d5bcd422
-
       # Workaround: https://github.com/docker/build-push-action/issues/461
       - name: Setup Docker buildx
         uses: docker/setup-buildx-action@79abd3f86f79a9d68a23c75a09a9a85889262adf
@@ -76,19 +70,3 @@ jobs:
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
-
-      # Sign the resulting Docker image digest except on PRs and private repos
-      # The keyless signing process records signatures on the Rekor public
-      # transparency log, so signing is disabled for private repos by default
-      # to avoid leaking private data.  If you wish to sign things anyways,
-      # then this check can be removed and --force can be added to the cosign
-      # command below.
-      # https://github.com/sigstore/cosign
-      - name: Sign the published Docker image
-        if: ${{ github.event_name != 'pull_request' && !github.event.repository.private }}
-        env:
-          COSIGN_EXPERIMENTAL: "true"
-        # This step uses the identity token to provision an ephemeral certificate
-        # against the sigstore community Fulcio instance, and records it to the
-        # sigstore community Rekor transparency log.
-        run: cosign sign ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}@${{ steps.build-and-push.outputs.digest }}