Include 2.6.0 and 3.0 snapshots in reference docs

Author: eleftherias

spring-session-docs/antora-playbook.yml

@@ -9,8 +9,8 @@ content:
     - url: https://github.com/spring-io/spring-generated-docs
       branches: [spring-projects/spring-session/*]
     - url: https://github.com/spring-projects/spring-session
-      branches: [main]
-      tags: ['2.6.*','!2.6.0-M*']
+      branches: [main,3.0.x]
+      tags: ['2.6.*','!2.6.0-M*','!2.6.0-RC*']
       start_path: spring-session-docs
 urls:
   latest_version_segment_strategy: redirect:to