Update CHANGELOG.md

Author: klew

CHANGELOG.md

@@ -16,6 +16,7 @@
   - Add: (ESP8266 RTOS, ESP IDF, Linux, FreeRTOS) `ChannelState` basic data reporting
   - Add: (ESP8266 RTOS, ESP IDF) `Supla::Storage` implementation on `spiffs`
   - Add: getters for electricity meter measured values
+  - Add: PZEMv3 with custom PZEM address setting (allow to use single TX/RX pair for multiple PZEM units)
 
 ## 2.4.0 (2021-12-07)