cache: enable for package step

.gitlab-ci.yml

@@ -140,6 +140,10 @@ package:
     - make -C gluon update GLUON_SITEDIR="$CI_PROJECT_DIR"
     - for branch in "stable" "beta" "nightly" "experimental"; do make -C gluon manifest GLUON_BRANCH="$branch" GLUON_SITEDIR="$CI_PROJECT_DIR" V=1; done
     - if [ -n "$GLUON_SIGN_KEY" ]; then cd gluon && for branch in "nightly" "experimental"; do ./contrib/sign.sh <(echo "$GLUON_SIGN_KEY") "output/images/sysupgrade/$branch.manifest"; done; fi
+  cache:
+    paths:
+      - gluon/openwrt/dl
+    key: "package"
   artifacts:
     paths:
       - gluon/output