Add Egyptian holidays

[wessama]

Public holidays in Egypt, both observed and national holidays, including checks for whether or not a holiday falls on a weekday/weekend and when it should be observed. This is synced with the way Google Calendar does it.

As noted in #56 and #90, the use of geniusts/hijri-dates is necessary to (pretty much) accurately calculate when Islamic holidays will be observed during a given year. When they're observed differs from one country to another, even if they're all celebrated concurrently.

All tests pass.

[stevebauman]

Underlying package is abandoned and also doesn't have any tests -- would be very skeptical to depend on it.

It is also restricted to Carbon v1 & v2, which is preparing to have a new v3 release soon, so this package will be incompatible with Laravel 11: laravel/framework#49764

[wessama]

Underlying package is abandoned and also doesn't have any tests -- would be very skeptical to depend on it.

It is also restricted to Carbon v1 & v2, which is preparing to have a new v3 release soon, so this package will be incompatible with Laravel 11: laravel/framework#49764

Thanks. I'm working together with a few other PR authors to come up with a way to centralize this logic in the Country class.

[wessama]

@Nielsvanpach I understand your hesitance to rely on an outdated package (one without tests, as well). So I adopted the Turkey approach in #70 and added those holidays statically. But I couldn't find a source that has been reliably tracking these holidays in Egypt prior to 2005. I double checked with Google Calendar and a few other sources, but the information on Wikipedia is incorrect.

You might know by now that there's no way to accurately predict when these holidays will be observed because of the variance involved, but this provides as good an approach as any (to my knowledge, anyway. I'd welcome anyone to correct this). Maybe this can be maintained in the future to add any drastic changes.

But apart from Islamic holidays, everything else can be precisely calculated.

I also found conflicts on the main branch with the Egypt class, which previously didn't account for Islamic holidays at all (and those actually factor into the fiscal year here and shouldn't be ignored, not by any reliable source of information anyway. I'd hate to be a business relying on this package only to find out it doesn't match real calendars). We've also been provided days off in lieu of national holidays that fall on a weekday or a weekend (which is Friday and Saturday here) for the past 3-4 years, this was also absent in the existing Egypt class. Variable holidays like the "Spring Festival" were also hardcoded even though this method in the Country class can be used.

holidays/src/Countries/Country.php

Line 57 in 6b35af7

protected function orthodoxEaster(int $year): CarbonImmutable

Other than that, I found the existing lang translations a bit too Google translate-ish so I replaced them with more sensible, true-to-life translations and added missing ones:

• https://github.com/spatie/holidays/blob/c30b89bd97f29db8402f96653617593dcdfd3be5/lang/egypt/ar/holidays.json

...and used the Egyptian Presidency's calendar for reference.

I kept the original snapshot to keep myself honest. All tests still pass.

[Nielsvanpach]

Thanks!