Add Execa to list of users

[ehmicky]

Thanks for this great library!

sindresorhus/execa#1120

[mre]

Thanks for mentioning, and thanks for using lychee. 😊

[mre]

The per-host rate-limiting is definitely planned. It's something we'll need urgently.
While it's true that lychee finished in 2 seconds, the reason is that the server's rate limiting immediately replied with a 429 and did so for all parallel requests. As such, lychee is mostly limited by the number of requests a server can handle, and we need to avoid overloading a server.