feat: Add description for multi-platform image

Closes #192

.github/workflows/build-and-test.yml

@@ -26,10 +26,10 @@ jobs:
         uses: actions/checkout@v3
 
       - name: Set up QEMU
-        uses: docker/setup-qemu-action@v2.1.0
+        uses: docker/setup-qemu-action@v2
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v2.5.0
+        uses: docker/setup-buildx-action@v2
         with:
           driver-opts: network=host
 
@@ -60,11 +60,13 @@ jobs:
           echo "Cache contents available at: ${CACHE_PATH}"
 
       - name: Build docker-salt-master image
-        uses: docker/build-push-action@v4.0.0
+        uses: docker/build-push-action@v4
         with:
           context: .
           file: ./Dockerfile
           platforms: linux/amd64,linux/arm64
+          outputs: |
+            type=image,annotation-index.org.opencontainers.image.description=salt-master latest containerized
           cache-from: |
             type=local,src=${{ env.CACHE_PATH }}
             ghcr.io/cdalvaro/docker-salt-master:latest