fix ARCH REL

Dockerfile

@@ -7,8 +7,8 @@ ARG BUILD_APP_VERSION
 ARG BUILD_S6_ARCH_amd64
 ARG BUILD_S6_OVERLAY_VERSION
 ARG ROOTFS=/root-out
-ARG REL=${BUILD_DEBIAN_REL}
-ARG ARCH=${BUILD_DEBIAN_ARCH}
+ARG BUILD_DEBIAN_REL
+ARG BUILD_DEBIAN_ARCH
 ARG MIRROR=http://dl-cdn.alpinelinux.org/alpine
 ARG PACKAGES=alpine-baselayout,\
 alpine-keys,\
@@ -30,7 +30,7 @@ RUN \
   mkdir /root-out && \
   curl -o \
     /rootfs.tar.gz -L \
-    https://github.com/debuerreotype/docker-debian-artifacts/raw/refs/heads/dist-${ARCH}/${REL}/slim/oci/blobs/rootfs.tar.gz && \
+    https://github.com/debuerreotype/docker-debian-artifacts/raw/refs/heads/dist-${BUILD_DEBIAN_ARCH}/${BUILD_DEBIAN_REL}/slim/oci/blobs/rootfs.tar.gz && \
   tar xf \
     /rootfs.tar.gz -C \
     /root-out && \