diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3f3df00..fcfc38c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -22,4 +22,4 @@ jobs:
         with:
           crane-version: "0.19.0"
       - name: Copy images
-        run: crane copy --all-tags docker.io/heroku/procfile-cnb docker.io/heroku/buildpack-procfile
+        run: crane copy --all-tags --jobs 1 docker.io/heroku/procfile-cnb docker.io/heroku/buildpack-procfile