Add What's New Link to Landing Pages

- to the README
- to the Reference index page

Author: jzheaux

README.adoc

@@ -21,6 +21,8 @@ See https://docs.spring.io/spring-security/reference/getting-spring-security.htm
 Be sure to read the https://docs.spring.io/spring-security/reference/[Spring Security Reference].
 Extensive JavaDoc for the Spring Security code is also available in the https://docs.spring.io/spring-security/site/docs/current/api/[Spring Security API Documentation].
 
+You may also want to check out https://docs.spring.io/spring-security/reference/whats-new.html[what's new in the latest release].
+
 == Quick Start
 See https://docs.spring.io/spring-security/reference/servlet/getting-started.html[Hello Spring Security] to get started with a "Hello, World" application.
 

docs/modules/ROOT/pages/index.adoc

@@ -12,4 +12,6 @@ If you are ready to start securing an application see the Getting Started sectio
 If you want to understand how Spring Security works, you can refer to the xref:servlet/architecture.adoc[Architecture] section.
 // FIXME add link to reactive architecture
 
+If you are already familiar with Spring Security or are upgrading, check out https://docs.spring.io/spring-security/reference/whats-new.html[what's new in the latest release].
+
 If you have any questions, there is a wonderful xref:community.adoc[community] that would love to help you!