bump server version in tests

Author: alexbozhenko

.github/workflows/test.yml

@@ -18,7 +18,7 @@ jobs:
             fail-fast: false
             matrix:
                 python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
-                nats_version: ["v2.10.29", "v2.11.6", "main"]
+                nats_version: ["v2.10.29", "v2.11.8", "main"]
                 include:
                     - nats_version: "main"
                       continue-on-error: true