some ideas for `nupm update`

i just wanted to throw this script in there, in case it can give inspiration to someone to write nupm update 🙏

# install a Nushell package without installing `nupm`
def nupm-install [
    package: path,  # the path to the local package to install
    --log-level: string = "DEBUG"  # the log level for the install
    --nupm: path,  # the path to the `nupm`'s directory
]: nothing -> nothing {
    nu --commands $"
        use ($nupm)
        NU_LOG_LEVEL=($log_level) nupm install --path ($package)
    "
}

alias "nupm install" = nupm-install --nupm (
    $env.GIT_REPOS_HOME | path join "github.com" "nushell" "nupm" "nupm"
)

def "nupm update" [repos: list<string>]: nothing -> nothing {
    for repo in $repos {
        let package = $env.GIT_REPOS_HOME | path join $repo

        git -C $package pull origin main
        nupm install $package
    }
}

nupm update [
    "github.com/goatfiles/scripts/nu_scripts"
    "github.com/amtoine/nu-git-manager"
    "github.com/amtoine/zellij-layouts/nu-zellij"
    "github.com/nushell/nu_scripts"
]

Start with the issue's nupm update example and the existing nupm install command it invokes. Define the expected repository inputs, pull behavior, and successful completion criteria before locating the implementation and tests.