cgmath is nice, but it uses old Rust 2015 and hasn't been updated since January 2021.
I can't imagine any obvious reason I would miss Rust's 2018 edition, let alone 2024 edition, to implement linear algebra? People seemed happy enough in Fortran before I was old enough to go to school and I don't sense it's an application where I'd want async for example. A lot of other edition changes are nice when writing new thing but not helpful for an existing codebase. So, like, sure, it's 2015 edition but that's fine?
There's actually an advantage to using older editions, and that is that it lowers the MSRV (minimum supported Rust version). This is especially nice for libraries, while binary project usually can just use the latest edition.