Add Australian Holidays

[patrickomeara]

These are the national holidays down to the state level.

[Nielsvanpach]

Thanks! I'll leave this open until this has some approvals by others.

[samlev]

Looks good to me without going into the absolute absurdity that is "replacement public holidays" (i e. those certain public holidays that fall on a weekend so some states give a "replacement" public holiday on the following Monday)

[patrickomeara]

Thanks @samlev I did think about the replacement days but decided against implementing something at this stage. The context of how the package is being used is a big factor to whether replacement days are useful or not.

[patrickomeara]

The tests seem a little flaky, when running all the tests locally I get between 1 and 3 fails. Uganda, Estonia and North Macedonia.

[Nielsvanpach]

Thanks, PR looks good! I'll have a look at the failing tests.