Add ChangeLog entry for CCM*

CCM* in PR #1667 is a feature and a functional enhancement and was missing a
ChangeLog entry.
diff --git a/ChangeLog b/ChangeLog
index b8a3879..23e0466 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,6 +7,7 @@
     cipher abstraction module.
   * Implement the HMAC-based extract-and-expand key derivation function
     (HKDF) per RFC 5869. Contributed by Thomas Fossati.
+  * Add support for the CCM* block cipher mode as defined in IEEE Std. 802.15.4.
 
 Bugfix
   * Fix the cert_write example to handle certificates signed with elliptic