update to CoSign v2.6.1

Author: wollomatic

.github/workflows/docker-image-release.yaml

@@ -39,7 +39,7 @@ jobs:
       - name: Install Cosign
         uses: sigstore/cosign-installer@v4.0.0
         with:
-          cosign-release: 'v2.6.0'
+          cosign-release: 'v2.6.1'
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3