chore(ci): avoid publishing images in reusable_build_docker.yaml workflow.

Instead, store image tarballs as artifact and download them in `reusable_publish_docker.yaml` workflow,
to be finally merged in multi-arch images and pushed.

Signed-off-by: Federico Di Pierro <nierro92@gmail.com>

.github/workflows/reusable_publish_docker.yaml

@@ -6,6 +6,19 @@ jobs:
   publish-docker:
     runs-on: ubuntu-latest
     steps:
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+    
+      - name: Download images tarballs
+        uses: actions/download-artifact@v3
+        with:
+          name: falco-images
+          path: /tmp
+      
+      - name: Load all images
+        run: |
+          for img in /tmp/falco-images/falco-*.tar; do docker load --input $img; done
+    
       - name: Login to Docker Hub
         uses: docker/login-action@v2
         with: