add changelog for v.0.4

Author: zapodot

README.md

@@ -14,6 +14,7 @@ This library is distributed through the [Sonatype OSS repo](https://oss.sonatype
 Java 7 or higher is required. It is currently at an early stage of development so breaking changes may occur :-)
 
 ## Changelog
+* version 0.4: [changelog](releases/tag/v.0.4)
 * version 0.3: solves [issue #1](issues/1) - give access to the LDAPConnection object from the UnboundID LDAP SDK 
 * version 0.2:
     * support for defining schema definitions using the "withSchema(String...)" method on the EmbeddedLdapRuleBuilder