contrib: rust: update the Rust version to 1.79.0

*-pc-windows-gnullvm is not accepted by rustup before that.

Note starting with Rust 1.78.0 the minimum version of Windows is Windows 10 [1] [2]. If we want Rust in Win7 we might want to select a different Rust version.

[1] https://blog.rust-lang.org/2024/05/02/Rust-1.78.0.html#compatibility-notes [2] https://blog.rust-lang.org/2024/02/26/Windows-7.html