Good friday US holiday not added in calendar

[tomassar]

Hi there, just a quick question, why isnt the Good Friday holiday added in the US holidays?

var GoodFriday = &cal.Holiday{
	Name:  "Good Friday",
	Month: time.March,
	Day:   29,
	Func:  cal.CalcDayOfMonth,
}

I can easily submit a PR but before I need to know if there's a good reason to ignore it.

[rickar]

There isn’t a technical reason or anything. So far I only added federal holidays where most businesses close because that’s all I needed personally. I assumed other religious holidays and special days would be added eventually. Feel free to add it.

[tomassar]

Got it, will submit a PR