Upgrading packages in Cargo.toml

I wanted to upgrade all packages listed in my Cargo.toml-file. Cargo has
a command to update all packages in Cargo.lock (cargo update), but this
leaves the Cargo.toml file untouched.

Weird that this functionality is not included in the standard Cargo
commands. But I found a cargo-edit on github:
https://github.com/killercup/cargo-edit.

It is easily installed with on command:

    cargo install cargo-edit

Now you can simply run cargo upgrade to change all versions mentioned in
you Cargo.toml file to the lastest version.