Update executables installed with cargo using the crate cargo-update.
cargo-update
To install: cargo install cargo-update
cargo install cargo-update
To update all installed crates: cargo install-update -a
cargo install-update -a
To update specific crates: cargo install-update crate1 crate2 ...
cargo install-update crate1 crate2 ...
More details at crates.io and GitHub.