Adding an update subcommand to install to update locally installed binaries

[cocool97]

Problem

It is currently a bit of a mess to update local installed binaries. We have to re-install all of them to get to the point.

The goal of the install subcommand would be only to install new packages (and throw an error if the package is already installed), and the update subcommand could update locally installed packages.

Proposed Solution

It could be a good idea to add an update subcommand to install to allow people to update one, more or all locally installed binaries.

Notes

No response

[Eh2406]

If the package is already installed, Cargo will reinstall it if the installed version does not appear to be up-to-date. If any of the following values change, then Cargo will reinstall the package:

https://doc.rust-lang.org/cargo/commands/cargo-install.html

Also cargo update is an existing command that is entirely unrelated.

[ehuss]

Yea, cargo install already updates packages if they are out of date. Updating all out-of-date packages is tracked in other issues like #9527, so closing as a duplicate of that.