Bump down cores, running into default quotas

Author: dconnolly

.github/workflows/test.yml

@@ -53,7 +53,7 @@ jobs:
           --boot-disk-type pd-ssd \
           --image-family cos-stable \
           --image-project cos-cloud \
-          --machine-type n2-standard-16 \
+          --machine-type n2-standard-4 \
           --service-account [email protected] \
           --scopes cloud-platform \
           --tags zebrad \