Keep fast sleep but only print 'waiting' once

.github/workflows/cd.yml

@@ -96,7 +96,7 @@ jobs:
       - name: Run acceptance tests
         run: |
           gcloud compute ssh "zebra-tests-$BRANCH_NAME-$SHORT_SHA" --zone us-central1-a \
-          --command "until [[ -n \$(docker ps --all -q --filter name=zebra-test) ]]; do echo 'waiting for zebra-test'; sleep 1; done; docker attach \$(docker ps -q -a --filter name=zebra-test)"
+          --command "echo 'Pulling container image...'; until [[ -n \$(docker ps --all -q --filter name=zebra-test) ]]; do sleep 0.1; done; docker attach \$(docker ps -q -a --filter name=zebra-test)"
 
       # Clean up
       - name: Delete test instance