Add fast-cli to "Who's using Ink" section

Author: sindresorhus

readme.md

@@ -89,6 +89,7 @@ Feel free to play around with the code and fork this repl at [https://repl.it/@v
 - [git-contrib-calendar](https://github.com/giannisp/git-contrib-calendar) - Display a contributions calendar for any git repository.
 - [gitgud](https://github.com/GitGud-org/GitGud) - An interactive command-line GUI for Git.
 - [Autarky](https://github.com/pranshuchittora/autarky) - An interactive CLI to find and delete old `node_modules` directories in order to free up disk space.
+- [fast-cli](https://github.com/sindresorhus/fast-cli) - Test your download and upload speed.
 
 ## Contents