Cloud Build wants underscores

Author: glasnt

build/int.cloudbuild.yaml

@@ -36,8 +36,8 @@ steps:
 
       # Do not prune if changing tests themselves
       git diff --quiet origin/main build test .github/workflows
-      CHANGED=$?
-      if [[ "${CHANGED}" -ne 0 ]]; then
+      _CHANGED=$?
+      if [[ "${_CHANGED}" -ne 0 ]]; then
           echo "Infrastructure folders have changed; no tests will be pruned."
           exit 0 # do not prune
       fi