feat: upgrade to bobcat (#887)

diff --git a/images/tempest/Earthfile b/images/tempest/Earthfile
index 062d82a..9f180c7 100644
--- a/images/tempest/Earthfile
+++ b/images/tempest/Earthfile
@@ -1,18 +1,21 @@
 VERSION 0.7
 
+ARG --global PROJECT=tempest
+ARG --global RELEASE=master
+ARG --global PROJECT_REF=699749ec27897efe9bd7824664237c16c3339c03
+
+build:
+  FROM ../openstack-service+builder --RELEASE=${RELEASE}
+  DO ../openstack-service+BUILD_VENV \
+    --PROJECT=${PROJECT} \
+    --PROJECT_REF=${PROJECT_REF} \
+    --PIP_PACKAGES="git+https://github.com/openstack/barbican-tempest-plugin.git git+https://github.com/openstack/cinder-tempest-plugin.git git+https://github.com/openstack/heat-tempest-plugin.git git+https://github.com/openstack/keystone-tempest-plugin.git git+https://github.com/openstack/neutron-tempest-plugin.git"
+
 image:
-  ARG PROJECT=tempest
-  ARG RELEASE=master
-  ARG REF=699749ec27897efe9bd7824664237c16c3339c03
-  FROM ../openstack-service+image \
-    --PROJECT ${PROJECT} \
-    --RELEASE ${RELEASE} \
-    --PROJECT_REF ${REF} \
-    --PIP_PACKAGES "git+https://github.com/openstack/barbican-tempest-plugin.git git+https://github.com/openstack/cinder-tempest-plugin.git git+https://github.com/openstack/heat-tempest-plugin.git git+https://github.com/openstack/keystone-tempest-plugin.git git+https://github.com/openstack/neutron-tempest-plugin.git"
-  DO \
-    ../+APT_INSTALL \
+  FROM ../openstack-service+image --RELEASE ${RELEASE} --PROJECT ${PROJECT}
+  COPY +build/venv /var/lib/openstack
+  DO ../+APT_INSTALL \
     --PACKAGES "iputils-ping"
-  DO ../+APPLY_PATCHES
   SAVE IMAGE --push \
     ghcr.io/vexxhost/atmosphere/${PROJECT}:${RELEASE} \
-    ghcr.io/vexxhost/atmosphere/${PROJECT}:${REF}
+    ghcr.io/vexxhost/atmosphere/${PROJECT}:${PROJECT_REF}