dev: Update CHANGELOG

Author: halimi

CHANGELOG.md

@@ -11,6 +11,8 @@ For details about compatibility between different releases, see the **Commitment
 
 ### Added
 
+- The NS resends the class C confirmed downlink after the `mac_settings.class_c_timeout` time.
+
 ### Changed
 
 - Increased the default value from 5 to 15 for maximum number of confirmed uplink retransmission for LoRaWAN version prior 1.0.4.