Switch to 2024 edition

Since the `VaList` implementation recently changed [1], making the
current incompatible with older Rust versions anyway, might as well
switch to the current edition.

[1]: #45

Author: nicholasbishop

Cargo.toml

@@ -4,7 +4,7 @@ description = "printf reimplemented in Rust"
 version = "0.2.1"
 repository = "https://github.com/lights0123/printf-compat"
 authors = ["lights0123 <[email protected]>"]
-edition = "2021"
+edition = "2024"
 license = "MIT OR Apache-2.0"
 readme = "README.md"