Update to Zig 0.16.0 (#962)

Signed-off-by: AnErrupTion <anerruption@disroot.org>

## What are the changes about?

Ports the code base to Zig 0.16.0.

## What existing issue does this resolve?

N/A

## Pre-requisites

- [x] I have tested & confirmed the changes work locally
- [x] I have run `zig fmt` throughout my changes

Reviewed-on: https://codeberg.org/fairyglade/ly/pulls/962

readme.md

@@ -14,7 +14,7 @@ Join us on Matrix over at [#ly-dm:matrix.org](https://matrix.to/#/#ly-dm:matrix.
 ## Dependencies
 
 - Compile-time:
-  - zig 0.15.x
+  - zig 0.16.x
 
   - libc