Updated GPU resource reservations to docker-compose

Original version was failing on Ubuntu EC2 instance with GPU - error message was:

'validating /home/ubuntu/.openrag/tui/docker-compose.gpu.yml: services.openrag-backend Additional property gpus is not allowed
Command exited with status 15

docker-compose.gpu.yml

@@ -3,5 +3,10 @@ services:
     environment:
       - NVIDIA_DRIVER_CAPABILITIES=compute,utility
       - NVIDIA_VISIBLE_DEVICES=all
-    gpus: all
-
+    deploy:
+      resources:
+        reservations:
+          devices:
+            - driver: nvidia
+              count: all
+              capabilities: [gpu]