CI: simplify pattern for job artifacts

There's no -diff job which would need artifacts anymore. We've long
switched to a CI setup where the diffing job is a standalone one that
does not need access to the original dependencies anymore.

Change-Id: I8633452f5b538e95bfb145cdec7400e7f8f0cf5a
diff --git a/ci/build.sh b/ci/build.sh
index c9d8d93..1ce6c23 100755
--- a/ci/build.sh
+++ b/ci/build.sh
@@ -73,7 +73,7 @@
 
 if [[ -z "${ARTIFACT_URL}" ]]; then
     # fallback to a promoted artifact
-    ARTIFACT_URL="https://object-store.cloud.muni.cz/swift/v1/ci-artifacts-${ZUUL_TENANT}/${ZUUL_GERRIT_HOSTNAME}/CzechLight/dependencies/${ZUUL_JOB_NAME%%-cover?(-previous|-diff)}/${DEP_SUBMODULE_COMMIT}.tar.zst"
+    ARTIFACT_URL="https://object-store.cloud.muni.cz/swift/v1/ci-artifacts-${ZUUL_TENANT}/${ZUUL_GERRIT_HOSTNAME}/CzechLight/dependencies/${ZUUL_JOB_NAME%%-cover?(-previous)}/${DEP_SUBMODULE_COMMIT}.tar.zst"
 fi
 
 ARTIFACT_FILE=$(basename ${ARTIFACT_URL})