update rust version from 1.32.0 to 1.39.0
Install instructions call for rust 1.32.0. Later in the process, rust is upgraded to 1.39.0. This change installs rust 1.39.0 from the start, avoiding an unnecessary upgrade of rust.
@@ -19,7 +19,7 @@ and using Homebrew on macOS.
- You will probably want to add ``~/.cargo/bin`` to your system's ``PATH``
-- Rust v1.32.0 (``rustup default 1.32.0``)
+- Rust v1.39.0 (``rustup default 1.39.0``)
- Clippy (``rustup component add clippy``)
- Rustfmt (``rustup component add rustfmt``)
- gcc
