rustcをアップデートする方法

下記の一行をコマンドで実行するだけ。

rustup update

出力参考

rustup update
info: syncing channel updates for 'stable-x86_64-pc-windows-msvc'
warning: Signature verification failed for 'https://static.rust-lang.org/dist/channel-rust-stable.toml'
info: latest update on 2023-03-09, rust version 1.68.0 (2c8cc3432 2023-03-06)
info: downloading component 'rust-src'
info: downloading component 'cargo'
info: downloading component 'clippy'
info: downloading component 'rust-docs'
info: downloading component 'rust-std'
info: downloading component 'rustc'
 63.9 MiB /  63.9 MiB (100 %)  37.5 MiB/s in  1s ETA:  0s
info: downloading component 'rustfmt'
info: removing previous version of component 'rust-src'
info: removing previous version of component 'cargo'
info: removing previous version of component 'clippy'
info: removing previous version of component 'rust-docs'
info: removing previous version of component 'rust-std'
info: removing previous version of component 'rustc'
info: removing previous version of component 'rustfmt'
info: installing component 'rust-src'
info: installing component 'cargo'
info: installing component 'clippy'
info: installing component 'rust-docs'
 19.4 MiB /  19.4 MiB (100 %)   2.4 MiB/s in  6s ETA:  0s
info: installing component 'rust-std'
 27.6 MiB /  27.6 MiB (100 %)  12.7 MiB/s in  2s ETA:  0s
info: installing component 'rustc'
 63.9 MiB /  63.9 MiB (100 %)  13.8 MiB/s in  4s ETA:  0s
info: installing component 'rustfmt'
info: checking for self-updates
info: downloading self-update

  stable-x86_64-pc-windows-msvc updated - rustc 1.68.0 (2c8cc3432 2023-03-06) (from rustc 1.64.0 (a55dd71d5 2022-09-19))

info: cleaning up downloads & tmp directories