added note about platformio support

devkit-cayenne/README.md

@@ -33,4 +33,25 @@ Will use onboard ST-Link(Flasher/Debugger) to upload sketch.
 Download and Install required utility from ST [here](https://www.st.com/en/development-tools/stm32cubeprog.html).  
 
 Arduino IDE:  
-Select Tools -> Upload Method -> STM32CubeProgrammer(SWD)
+Select Tools -> Upload Method -> STM32CubeProgrammer(SWD)
+
+### PlatformIO Configuration 
+
+** If your
+
+```
+[env:disco_l072cz_lrwan1]
+platform = ststm32
+board = disco_l072cz_lrwan1
+framework = arduino
+
+lib_deps =
+     STM32duino LSM6DSO
+     STM32duino LIS2DW12
+     STM32duino STTS751
+     STM32duino LIS2MDL
+     STM32duino LPS22HH
+     STM32duino HTS221
+     MCCI LoRaWAN LMIC library
+     CayenneLPP
+```