chore(contrib): upgrade to 2024 edition

Part of #114
This edition change doesn't affect these crates except for formatting.

Change-Id: I441c967b6803f1f839379c2ec13dee3f0958fb05
Reviewed-on: https://cl.snix.dev/c/snix/+/30593
Autosubmit: Bence Nemes <nemes.bence1@gmail.com>
Reviewed-by: Ilan Joselevich <personal@ilanjoselevich.com>
Reviewed-by: Florian Klink <flokli@flokli.de>
Tested-by: besadii

contrib/fetchroots/src/main.rs

@@ -28,7 +28,7 @@ use nix_compat::nixbase32;
 use polars::prelude::*;
 use tokio::{
     sync::Semaphore,
-    task::{block_in_place, JoinSet},
+    task::{JoinSet, block_in_place},
 };
 
 #[derive(Debug)]