Retrieve today's date using the local timezone

[kwbr]

This fixes #127.

I abstained from adding a test as I have not found out how to handle different timezones with Janet's os package. (https://github.com/cosmictoast/janet-date does provide more flexibility in this regard)

There might be other bugs lurking when converting the dates back and forth.

[strika]

Looks good. Thanks. 👍

I don't remember why I didn't use janet-date. Maybe it wasn't available at the time or maybe it was missing something. In any case, I don't plan to adopt it at the moment.

[kwbr]

Thanks for merging that. How can I build a binary for Mac? Is there a way to do that with docker?

[strika]

Sorry, but I don't know about that. I'm primarily a Linux user. I use Docker on Linux. But I use an old Macbook Pro to build a binary for MacOS (x86_64). I don't use Docker when I do that.

If there is a way to build binaries for different systems on one platform, that would be great. Maybe you can ask at the Janet's forum - https://github.com/janet-lang/janet/discussions. Please tag me (if that's possible) if you do that.