ci: fix not signed to registry

Author: fredleger

.github/workflows/__shared-ci.yml

@@ -89,6 +89,12 @@ jobs:
       - hadolint
       - docker-build-images
     steps:
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+
       - name: install cosign
         uses: sigstore/cosign-installer@v3.7.0
         with: