Fix typo in 1.81.0 release

Author: Urgau

posts/2024-09-05-Rust-1.81.0.md

@@ -70,7 +70,7 @@ if code runs in an environment without floating point support, you could use
 Clippy to lint on such usage with `#![deny(clippy::float_arithmetic)]`.
 However, if a new developer to the project sees this lint fire, they need to
 look for (hopefully) a comment on the deny explaining why it was added. With
-Rust 1.71, they can be informed directly in the compiler message:
+Rust 1.81, they can be informed directly in the compiler message:
 
 ```text
 error: floating-point arithmetic detected