[feature request] Add helper to set last day of month

[everdimension]

Hello! Thanks a lot for this library.

I stumbled upon a case where I need to be able to set a "maximum" date for the current month. E.g.

dayjs().set('date', 'max'); // is it 30 or 31 or 28? I wish I could just tell the lib to pick the right one

What do you think? If you agree that it is a good idea I'd be glad to make a PR.
But I think the exact API should be discussed first.

Thanks!

[everdimension]

Oh, well, I just realized I can do this:

dayjs().set('date', 1).add(1, 'month').subtract(1, 'day');

:)

[iamkun]

You can use

dayjs().endOf('month')

[everdimension]

Oh, thanks!! Did not find that. I guess the issue is solved, then