Add changelog in What's New

Issue gh-3768

docs/manual/src/docs/asciidoc/index.adoc

@@ -372,6 +372,9 @@ This will give you access to the entire project history (including all releases
 [[new]]
 == What's New in Spring Security 4.1
 
+There were https://github.com/spring-projects/spring-security/milestones/4.1.0%20RC1[100+ issues] fixed in Spring Security 4.1.
+You can find the highlights below:
+
 * <<el-access-web-path-variables,Path Variables in Web Security Expressions>>
 * <<headers-csp,Content Security Policy (CSP)>>
 * <<headers-hpkp,HTTP Public Key Pinning (HPKP)>>