Bump to version 2.1.6

fix release note

Bump to version 2.1.4

Bump to version 2.1.3

Bump to version 2.1.2

Add some fixes for character device based implementation of Jetson.GPIO
Update PWM pins list for Jetson Orin NX and Jetson Orin Nano
Add tests for callbacks and epoll object dictionary for parallel events
Update README and multiple comments in the code

Bump to version 2.1.1

Add support for Jetson Orin NX and Jetson Orin Nano developer kit
Fix Jetson Nano and Jetson TX1 implementation

Update udev rules for character device implementation

Bump to version 2.0.22

Add Orin NX developer kit

Bump to version 2.0.21

Bump to version 2.0.20