deps: colorstring library is archived

The library we use for CLI coloring has not been committed to for 7 years and is archived: https://github.com/mitchellh/colorstring

We should look into migrating from this library to something that is maintained. [fatih/color](https://github.com/fatih/color) could be a candidate.

The issue identifies mitchellh/colorstring and suggests fatih/color, but names no files or tests. Start by locating the dependency's CLI-coloring usage and checking the candidate library's fit; done means the archived dependency has been replaced by a maintained alternative without losing the current coloring behavior.

Written by the indexing model from the issue text.