v1.4.0 to auto detect ESP32 core

#### Releases v1.4.0

##### Warning: Releases v1.4.0+ can be used and autodetect ESP32 core v2.0.0+ or v1.0.6-.

1. Auto detect ESP32 core
2. Renew examples
3. Display compiler `#warning` only when DEBUG_LEVEL is 3+

Author: khoih-prog

README.md

@@ -157,8 +157,8 @@ to apply the better and faster **asynchronous** feature of the **powerful** [ESP
 ## Prerequisites
 
  1. [`Arduino IDE 1.8.16+` for Arduino](https://www.arduino.cc/en/Main/Software)
- 2. [`ESP32 Core 2.0.1+`](https://github.com/espressif/arduino-esp32) for ESP32-based WT32_ETH01 boards using release v1.3.0+. [![Latest release](https://img.shields.io/github/release/espressif/arduino-esp32.svg)](https://github.com/espressif/arduino-esp32/releases/latest/)
- 3. [`ESP32 Core 1.0.6-`](https://github.com/espressif/arduino-esp32) for ESP32-based WT32_ETH01 boards using release v1.2.5- [![Latest release](https://img.shields.io/github/release/espressif/arduino-esp32.svg)](https://github.com/espressif/arduino-esp32/releases/latest/)
+ 2. [`ESP32 Core 2.0.1+`](https://github.com/espressif/arduino-esp32) for ESP32-based WT32_ETH01 boards using this library's release `v1.3.0+`. ESP32 Latest Core [![Latest release](https://img.shields.io/github/release/espressif/arduino-esp32.svg)](https://github.com/espressif/arduino-esp32/releases/latest/)
+ 3. [`ESP32 Core 1.0.6-`](https://github.com/espressif/arduino-esp32) for ESP32-based WT32_ETH01 boards using this library's release `v1.2.5-`. ESP32 Latest Core [![Latest release](https://img.shields.io/github/release/espressif/arduino-esp32.svg)](https://github.com/espressif/arduino-esp32/releases/latest/)
 
  4. [`AsyncTCP library v1.1.1+`](https://github.com/me-no-dev/AsyncTCP).