docker: build linux/arm64

Author: zg1r

.github/workflows/docker-build.yml

@@ -48,3 +48,4 @@ jobs:
           push: true
 #          tags: ${{ secrets.DOCKERHUB_USERNAME }}/sgroups.k8s.netguard:${{ github.head_ref || github.ref_name }}-${{ steps.short-sha.outputs.sha }}
           tags: ${{ secrets.DOCKERHUB_USERNAME }}/sgroups.k8s.netguard:${{ steps.sanitize.outputs.branch }}-${{ steps.short-sha.outputs.sha }}
+          platforms: linux/amd64,linux/arm64