ci: use docker buildx

Author: zuramai

.github/workflows/deploy.yml

@@ -25,6 +25,9 @@ jobs:
       with:
         images: zuramai/pembantu-ai
 
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v3
+
     - name: Build and push Docker image
       id: push
       uses: docker/build-push-action@v6