I want to add a PWM class according to the "peripheral class common specifications".
https://github.com/HirohitoHigashi/mruby_io_class_study

There are currently mruby-esp32-ledc and mruby-esp32-mcpwm as PWM implementation methods, but I want to use ledc in this class. This specification is based on MicroPython .
ref: #49 (comment)