Luxon: Info.weekdays seems to be mutable

[UnsungHero97]

Describe the bug
It seems that Info.weekdays is mutable and it affects DateTime instances.

To Reproduce
To reproduce, I just called .pop() on Info.weekdays in the console on your website:

https://moment.github.io/luxon/docs/class/src/datetime.js~DateTime.html

Here's a screenshot of the console:

Actual vs Expected behavior
Luxon claims to be immutable. My expectation is that running Info.weekdays('short') would give me a new copy of the array instead of a global constant that is used by DateTime instances.

Desktop (please complete the following information):

• macOS
• Chrome 86
• luxon v1.25.0

Additional context
The reason I am doing this is because I'm trying to get a copy of Info.weekdays('short') but with Sunday being at the beginning of the array.

[icambron]

Yeha, Luxon should copy the array before returning it. Would accept a PR

[UnsungHero97]

Thanks, @icambron. I'll put together a PR.

[UnsungHero97]

Sorry y'all, haven't had time to work on that pull request.

[dan-overton]

I had some time so opened a PR to fix this, any review would be appreciated.

[icambron]

Closed by #829