Feature Request: setXxx

[Toru-Takagi]

I apologize if my knowledge is lacking.
I would like to set specific months or dates (absolute values).

While I can manage with addXxx (relative values) by working hard on calculations, I would prefer to have setXxx if possible.

See: https://momentjscom.readthedocs.io/en/latest/moment/02-get-set/20-set/

While the browser functionality suffices and writing a bit of source code is all it takes, having it return an immutable Date is appreciated.

https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Date/setHours