Installation via `asdf` using plugin

[treezio]

Hi!

I've created an asdf plugin to manage gws installation which is available at https://github.com/treezio/asdf-gws

Instructions:

Add plugin:

asdf plugin add gws https://github.com/treezio/asdf-gws.git

Installation:

# Show all installable versions
asdf list-all gws

# Install specific version
asdf install gws latest

# Set a version globally (on your ~/.tool-versions file)
asdf set --home gws latest

Feel free to add this to the Installation section in the README.md file