Update What's New for 6.0

docs/modules/ROOT/pages/whats-new.adoc

@@ -7,4 +7,5 @@ Below are the highlights of the release.
 == Breaking Changes
 
 * https://github.com/spring-projects/spring-security/issues/8980[gh-8980] - Remove unsafe/deprecated `Encryptors.querableText(CharSequence,CharSequence)`.
-Instead use data storage to encrypt values.
+Instead use data storage to encrypt values.
+* https://github.com/spring-projects/spring-security/issues/11520[gh-11520] - Remember Me uses SHA256 by default