Update readme with MAVLink and SmartAudio/Tramp (ExpressLRS#2936)

Author: MUSTARDTIGERFPV

README.md

@@ -45,8 +45,8 @@ ExpressLRS has the following features:
 - Oled & TFT Displays
 - 2.4 GHz, 900 MHz, and Dual-Band RC Link
 - SMD Antenna - allows for easier installation into micros
-- Supported receiver protocols: CRSF, SBUS, SUMD, HoTT Telemetry, and PWM
-- VTX and VRX Frequency adjustments from the Lua
+- Supported receiver protocols: CRSF, SBUS, SUMD, HoTT Telemetry, MAVLink, and PWM
+- VTX and VRX Frequency adjustments from the Lua, including SmartAudio and Tramp support
 - Bind Phrases - no need for button binding
 
 with many more features on the way!