⬆️ Updated Liminal Express SDK

Updated the latest version of Liminal Express SDK to v1.3.8. Ensure to update the required impacted applications.

1. The Docker container image to /liminal-sdk-api:1.3.8. Refer to the Update Liminal Express guide to update to the latest version.
2. The Express Developer Postman collection. Refer to the following latest versions:
   • Liminal Express Developer_1.3.8 (v1).postman_collection,
   • Liminal Express Developer_1.3.8 (v2).postman_collection.