v1.2.0 add support to RP2040 ArduinoCore-mbed

### Releases v1.2.0

1. Add support to RP2040-based boards, such as **RASPBERRY_PI_PICO boards** using [**Arduino-mbed RP2040** core](https://github.com/arduino/ArduinoCore-mbed).
2. Fix compiler warnings

Author: khoih-prog

README.md

@@ -160,8 +160,8 @@ This [**ESP_AT_Lib** library](https://github.com/khoih-prog/ESP_AT_Lib) currentl
  7. [`Adafruit SAMD core 1.6.8+`](https://github.com/adafruit/ArduinoCore-samd) for SAMD ARM Cortex-M0+ and M4 boards (Nano 33 IoT, etc.). [![GitHub release](https://img.shields.io/github/release/adafruit/ArduinoCore-samd.svg)](https://github.com/adafruit/ArduinoCore-samd/releases/latest)
  8. [`Seeeduino SAMD core 1.8.1+`](https://github.com/Seeed-Studio/ArduinoCore-samd) for SAMD21/SAMD51 boards (XIAO M0, Wio Terminal, etc.). [![Latest release](https://img.shields.io/github/release/Seeed-Studio/ArduinoCore-samd.svg)](https://github.com/Seeed-Studio/ArduinoCore-samd/releases/latest/)
  9. [`Adafruit nRF52 v0.21.0+`](https://github.com/adafruit/Adafruit_nRF52_Arduino) for nRF52 boards such as Adafruit NRF52840_FEATHER, NRF52832_FEATHER, NRF52840_FEATHER_SENSE, NRF52840_ITSYBITSY, NRF52840_CIRCUITPLAY, NRF52840_CLUE, NRF52840_METRO, NRF52840_PCA10056, PARTICLE_XENON, **NINA_B302_ublox**, etc. [![GitHub release](https://img.shields.io/github/release/adafruit/Adafruit_nRF52_Arduino.svg)](https://github.com/adafruit/Adafruit_nRF52_Arduino/releases/latest)
-10. [`Earle Philhower's arduino-pico core v1.2.1+`](https://github.com/earlephilhower/arduino-pico) for RP2040-based boards such as **RASPBERRY_PI_PICO, ADAFRUIT_FEATHER_RP2040 and GENERIC_RP2040**, etc. [![GitHub release](https://img.shields.io/github/release/earlephilhower/arduino-pico.svg)](https://github.com/earlephilhower/arduino-pico/releases/latest)
-11. [`Arduino mbed_rp2040 core 2.0.0+`](https://github.com/arduino/ArduinoCore-mbed) for Arduino (Use Arduino Board Manager) RP2040-based boards, such as RASPBERRY_PI_PICO. [![GitHub release](https://img.shields.io/github/release/arduino/ArduinoCore-mbed.svg)](https://github.com/arduino/ArduinoCore-mbed/releases/latest)
+10. [`Earle Philhower's arduino-pico core v1.4.0+`](https://github.com/earlephilhower/arduino-pico) for RP2040-based boards such as **RASPBERRY_PI_PICO, ADAFRUIT_FEATHER_RP2040 and GENERIC_RP2040**, etc. [![GitHub release](https://img.shields.io/github/release/earlephilhower/arduino-pico.svg)](https://github.com/earlephilhower/arduino-pico/releases/latest)
+11. [`Arduino mbed_rp2040 core 2.1.0+`](https://github.com/arduino/ArduinoCore-mbed) for Arduino (Use Arduino Board Manager) RP2040-based boards, such as RASPBERRY_PI_PICO. [![GitHub release](https://img.shields.io/github/release/arduino/ArduinoCore-mbed.svg)](https://github.com/arduino/ArduinoCore-mbed/releases/latest)
 12. [`Ai-Thinker AT Firmware v1.5.4`](AT_Firmwares/At_firmware_bin1.54.zip) or [`AT Firmware v1.7.4.0`](AT_Firmwares/AT_Firmware_bin_1.7.4.0.zip) for ESP8266-AT shields.
 13. [`AT version_2.1.0.0_dev`](AT_Firmwares/AT_version_2.1.0.0_dev.zip) for ESP32-AT shields.
 14. `AT version_1.1.4` for WIS600-01S and W600-AT WiFi shields.