Update Rust version to 1.71 in Cargo.toml

Author: taiki-e

Cargo.toml

@@ -6,7 +6,7 @@ name = "async-fs"
 version = "2.1.3"
 authors = ["Stjepan Glavina <[email protected]>"]
 edition = "2021"
-rust-version = "1.63"
+rust-version = "1.71"
 description = "Async filesystem primitives"
 license = "Apache-2.0 OR MIT"
 repository = "https://github.com/smol-rs/async-fs"