Update to antora-ui-spring 0.3.5.

Closes gh-812

Author: rwinch

antora-playbook.yml

@@ -37,7 +37,7 @@ urls:
   redirect_facility: httpd
 ui:
   bundle:
-    url: https://github.com/spring-io/antora-ui-spring/releases/download/v0.3.3/ui-bundle.zip
+    url: https://github.com/spring-io/antora-ui-spring/releases/download/v0.3.5/ui-bundle.zip
     snapshot: true
 runtime:
   log: