specify gpu count in vllm sample

Author: jordanstephens

samples/vllm/compose.yaml

@@ -13,6 +13,7 @@ services:
           memory: 8192M
           devices:
             - capabilities: ["gpu"]
+              count: 1
     healthcheck:
       test: ["CMD", "python3", "-c", "import sys, urllib.request;urllib.request.urlopen(sys.argv[1]).read()", "http://localhost:8000/health"]
       interval: 1m