Enhance Docker workflow with multi-arch build platform detection

Author: BangerTech

.github/workflows/docker.yml

@@ -18,7 +18,13 @@ jobs:
         uses: docker/setup-qemu-action@v3
 
       - name: Set up Docker Buildx
+        id: buildx
         uses: docker/setup-buildx-action@v3
+        with:
+          version: latest
+
+      - name: Available platforms
+        run: echo ${{ steps.buildx.outputs.platforms }}
 
       - name: Login to Docker Hub
         uses: docker/login-action@v3
@@ -37,6 +43,7 @@ jobs:
           file: ./frontend/Dockerfile.prod
           push: true
           platforms: linux/amd64,linux/arm64
+          builder: ${{ steps.buildx.outputs.name }}
           tags: |
             bangertech/bambucam-frontend:latest
             bangertech/bambucam-frontend:${{ steps.tag.outputs.TAG }}
@@ -48,6 +55,7 @@ jobs:
           file: ./backend/Dockerfile.prod
           push: true
           platforms: linux/amd64,linux/arm64
+          builder: ${{ steps.buildx.outputs.name }}
           tags: |
             bangertech/bambucam-backend:latest
             bangertech/bambucam-backend:${{ steps.tag.outputs.TAG }}