add note about installation on platformIO (use lib_compat_mode = strict)

readme.md

@@ -40,16 +40,16 @@ Here the comparison against 2 similar and popular libraries:
 (1) In the worst case, with default settings
 (2) If the hardware timer allows it, otherwise it will be lower
 
-### Requirements
+## Installation
 
-You need Arduino IDE and the appropriate board packages. On AVR boards such as Arduino/Genuino Uno, you also need [ArduinoSTL](https://github.com/mike-matera/ArduinoSTL) (available on Arduino Library Manager).
-If you want to compile the 6th example (the most complete), you also need [ArduinoSerialCommand](https://github.com/kroimon/Arduino-SerialCommand) library.
+The latest version of Dimmable Light for Arduino is available on Arduino Library Manager and on [PlatformIO registry](https://registry.platformio.org/libraries/fabianoriccardi/Dimmable%20Light%20for%20Arduino).
 
-> :warning: *for AVR core*: use AVR Core v1.8.2 or lower. This is because an incompatibility between ArduinoSTL and new versions of AVR core, hopefully it will be soon solved.
+On AVR boards such as Arduino/Genuino Uno, you also need [ArduinoSTL](https://github.com/mike-matera/ArduinoSTL) (available on Arduino Library Manager).
+If you want to compile the 6th example (the most complete), you also need [ArduinoSerialCommand](https://github.com/kroimon/Arduino-SerialCommand) library.
 
-## Installation
+> 📝 *for AVR core*: use AVR Core v1.8.2 or lower. This is because an incompatibility between ArduinoSTL and new versions of AVR core.
 
-The latest version of Dimmable Light for Arduino is available on Arduino Library Manager and on [PlatformIO registry](https://registry.platformio.org/libraries/fabianoriccardi/Dimmable%20Light%20for%20Arduino).
+> 📝 *for PlatformIO users*: in `platformio.ini` file it is recommeded to add in `env` section the setting `lib_compat_mode = strict` to avoid conflicts with the default STL included in all environments (but not in Arduino-AVR core) and ArduinoSTL.
 
 ## Usage