Hijri calendar was not supported in Julia stdlib or any external package, so I tried to remedy the situation a little. I looked for Hijri packages in other languages that I could rewrite in Julia. It was suggested to me that thishttps://docs.oracle.com/javase/8/docs/api/java/time/chrono/HijrahChronology.html Java library would be a solid candidate. But I do not know Java, so I had to go for a Python package.
This package has one major caveat - supported date range. I intend to expand it in the future.
You can check out the progress (bug fixes, new features, versions, etc.) here.
Some feedback would be great. If anyone wants to contribute in any way, they are more than welcome. If someone intends to build a more solid Hijri package, I actually advocate for that.