Add buymeacoffee

Finally, in need of some real coffee ;=))

Author: khoih-prog

README.md

@@ -6,6 +6,9 @@
 [![contributions welcome](https://img.shields.io/badge/contributions-welcome-brightgreen.svg?style=flat)](#Contributing)
 [![GitHub issues](https://img.shields.io/github/issues/khoih-prog/SAMD_Slow_PWM.svg)](http://github.com/khoih-prog/SAMD_Slow_PWM/issues)
 
+<a href="https://www.buymeacoffee.com/khoihprog6" target="_blank"><img src="https://cdn.buymeacoffee.com/buttons/v2/default-yellow.png" alt="Buy Me A Coffee" style="height: 60px !important;width: 217px !important;" ></a>
+
+
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@@ -169,7 +172,7 @@ The catch is **your function is now part of an ISR (Interrupt Service Routine),
  1. [`Arduino IDE 1.8.19+` for Arduino](https://github.com/arduino/Arduino). [![GitHub release](https://img.shields.io/github/release/arduino/Arduino.svg)](https://github.com/arduino/Arduino/releases/latest)
  2. [`Arduino SAMD core 1.8.12+`](https://github.com/arduino/ArduinoCore-samd) for SAMD ARM Cortex-M0+ boards. [![GitHub release](https://img.shields.io/github/release/arduino/ArduinoCore-samd.svg)](https://github.com/arduino/ArduinoCore-samd/releases/latest)
  3. [`Adafruit SAMD core 1.7.8+`](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)
- 4. [`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/)
+ 4. [`Seeeduino SAMD core 1.8.2+`](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/)
  5. [`Sparkfun SAMD core 1.8.3+`](https://github.com/sparkfun/Arduino_Boards) for SAMD21/SAMD51 boards (SparkFun_RedBoard_Turbo, SparkFun_SAMD51_Thing_Plus, etc.).
 
  6. To use with certain example