message: Try another variable
  BRANCH is pull/xxxx/head so that doesn't work
diff: @@ -34,7 +34,7 @@ elif [[ "${#BUILDKITE_BRANCH_ARRAY[@]}" == "2" ]]; then
  fi
  # Try the target branch of the push or PR.
  clone $deforg $defrepo $BUILDKITE_PULL_REQUEST_BASE_BRANCH
  -# Try BRANCH which is set by Netlify
  -clone $deforg $defrepo $BRANCH
  +# Try HEAD which is set by Netlify
  +clone $deforg $defrepo $HEAD
  # Use the default branch as the last resort.
  clone $deforg $defrepo $defbranch
  