Add minimum & maximum day

[nicholaschong95]

Is it possible to add minimum and maximum date, not by year

[tahseen0amin]

Not yet but I will try to add this functionality as I have a requirement as well.

[tahseen0amin]

@nicholaschong95
added pull request.
#14

You can use the code from the commit.

I have also added separate repo for use for Swift Package Manager. check my repositories.