refactor: adapt to new rust version

Author: Kitt3120

Cargo.toml

@@ -3,7 +3,7 @@ name = "lum_config"
 version = "0.2.5"
 authors = ["Torben Schweren"]
 edition = "2024"
-rust-version = "1.85.0"
+rust-version = "1.88.0"
 description = "lum framework's config library"
 readme = "README.md"
 repository = "https://github.com/lum-rs/lum_config"