v1.2.0 to autodetect ESP32 core version

### Releases v1.2.0

1. Auto detect ESP32 core and use either built-in LittleFS or [LITTLEFS](https://github.com/lorol/LITTLEFS) library
2. Update `library.json` to use new `headers` for PIO

Author: khoih-prog

README.md

@@ -102,7 +102,7 @@ This [**ESP_DoubleResetDetector** library](https://github.com/khoih-prog/ESP_Dou
 2. [`ESP32 Core 2.0.1+`](https://github.com/espressif/arduino-esp32) for ESP32-based boards. [![Latest release](https://img.shields.io/github/release/espressif/arduino-esp32.svg)](https://github.com/espressif/arduino-esp32/releases/latest/)
 3. [`ESP8266 Core 3.0.2+`](https://github.com/esp8266/Arduino) for ESP8266-based boards. [![Latest release](https://img.shields.io/github/release/esp8266/Arduino.svg)](https://github.com/esp8266/Arduino/releases/latest/). SPIFFS is deprecated from ESP8266 core 2.7.1+, to use LittleFS. 
 
-4. [`LITTLEFS v1.0.6+`](https://github.com/lorol/LITTLEFS) for ESP32-based boards using LittleFS with ESP32 core v1.0.4-. To install, check [![arduino-library-badge](https://www.ardu-badge.com/badge/LittleFS_esp32.svg?)](https://www.ardu-badge.com/LittleFS_esp32). **Notice**: This [`LITTLEFS library`](https://github.com/lorol/LITTLEFS) has been integrated to Arduino [ESP32 core v1.0.6+](https://github.com/espressif/arduino-esp32/tree/master/libraries/LITTLEFS) and you don't need to install it if using ESP32 core v1.0.6+
+4. [`LittleFS_esp32 v1.0.6+`](https://github.com/lorol/LITTLEFS) for ESP32-based boards using LittleFS with ESP32 core v1.0.4-. To install, check [![arduino-library-badge](https://www.ardu-badge.com/badge/LittleFS_esp32.svg?)](https://www.ardu-badge.com/LittleFS_esp32). **Notice**: This [`LittleFS_esp32 library`](https://github.com/lorol/LITTLEFS) has been integrated to Arduino [ESP32 core v1.0.6+](https://github.com/espressif/arduino-esp32/tree/master/libraries/LITTLEFS) and you don't need to install it if using ESP32 core v1.0.6+
 
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