Update antora-playbook.yml to 0.4.11

Author: Ryan Baxter

docs/antora-playbook.yml

@@ -36,4 +36,4 @@ runtime:
     format: pretty
 ui:
   bundle:
-    url: https://github.com/spring-io/antora-ui-spring/releases/download/v0.4.2/ui-bundle.zip
+    url: https://github.com/spring-io/antora-ui-spring/releases/download/v0.4.11/ui-bundle.zip