Add matrix build for different archs

.github/workflows/build.yml

@@ -6,6 +6,14 @@ on:
 jobs:
   docker:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        arch: [amd64, arm64/v8]
+        variant:
+          - name: nf_tables
+            use_iptables_legacy: "false"
+          - name: legacy
+            use_iptables_legacy: "true"
     steps:
       - name: Log into DockerHub
         if: github.event_name != 'pull_request'
@@ -25,11 +33,19 @@ jobs:
         uses: docker/metadata-action@v5
         with:
           images: ${{ github.actor }}/ufw-docker-agent
+          tags: |
+            type=schedule,suffix=${{ matrix.variant.name }}
+            type=ref,event=branch,suffix=${{ matrix.variant.name }}
+            type=ref,event=pr,suffix=${{ matrix.variant.name }}
+            type=semver,pattern={{version}},suffix=${{ matrix.variant.name }}
+            type=sha,suffix=${{ matrix.variant.name }}
 
       - name: Build and push
         uses: docker/build-push-action@v6
         with:
           push: ${{ github.event_name != 'pull_request' }}
-          platforms: linux/amd64,linux/arm64/v8
+          platforms: linux/${{ matrix.arch }}
+          build-args: |
+            use_iptables_legacy=${{ matrix.variant.use_iptables_legacy }}
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}