ci: fix build cache (#950)

diff --git a/images/glance/Earthfile b/images/glance/Earthfile
index 25e298e..2646670 100644
--- a/images/glance/Earthfile
+++ b/images/glance/Earthfile
@@ -1,6 +1,5 @@
 VERSION 0.7
 
-ARG --global REGISTRY=ghcr.io/vexxhost/atmosphere
 ARG --global PROJECT=glance
 ARG --global RELEASE=2023.2
 ARG --global PROJECT_REF=9a4a3067b5c7c7f8ee9363bd939a3d86b260d660
@@ -27,6 +26,7 @@
   COPY ../kubernetes+image/kubectl /usr/local/bin/kubectl
   DO ../+APT_INSTALL \
     --PACKAGES "ceph-common lsscsi nvme-cli python3-rados python3-rbd qemu-utils sysfsutils udev util-linux"
+  ARG REGISTRY=ghcr.io/vexxhost/atmosphere
   SAVE IMAGE --push \
     ${REGISTRY}/${PROJECT}:${RELEASE} \
     ${REGISTRY}/${PROJECT}:${PROJECT_REF}