allow empty path (#325)

* create a dummy app just for faster integration test

* fix docker-auth script to accept empty path

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Co-authored-by: Yu Hu <yuhuyoyo@verily.health>

Author: yuhuyoyo

startupscript/butane/gcp/docker-auth.sh

@@ -9,7 +9,7 @@ set -o nounset
 set -o pipefail
 
 # Validate required parameter
-if [ $# -lt 1 ] || [ -z "${1:-}" ]; then
+if [ $# -lt 1 ]; then
     echo "Error: path parameter is required" >&2
     echo "Usage: $0 <path> [default-regions]" >&2
     exit 1