Provide a simple way to upgrade the tools

As I understand, to upgrade a tool we need to re-run the same command than for the installation, replacing the version.

It will be good for the sake of simplicity and to avoid the rot of the tool versions, to have a way to upgrade easily the different tools.

It could be a command: gruntwork upgrade. It will require of course some metadata regarding the list of the tools installed.

Did you considered using existing package managers (brew, apt-get, ...) ? There are solving lots of problems than new coming packing managers will face sooner or later.

I understand than some of your tools are private. Brew seems to provide [a way to support this](https://vanwollingen.nl/distributing-private-tools-through-homebrew-d046761fb3a1).

The issue does not name files, tests, or an entry point. Start by tracing the existing tool installation command and how installed tools are tracked, then determine the metadata and package-manager scope needed for upgrades. Done means the project has a defined, tested way to upgrade installed tools without manually replacing versions.

Written by the indexing model from the issue text.