There are a few Lua implementations written in Go already, but Microsoft found none that target Lua 5.3, so they set out to develop their own as MIT licensed Open Source, with a focus on better error handling and debugging, clean and idiomatic Go APIs, and more closely following the Lua spec than other implementations. It's called Golua and is on Github, from the Microsoft Azure team.
One commenter on Hacker News was quick to point out his own Lua 5.3 engine written in Go, also called Golua. Oops :) But the goals are probably still very different. Using the same name is unfortunate however.
There aren't any examples or documentation for Microsoft's Golua yet, they didn't expect anyone to notice it that soon after putting it on Github, which seems a bit weird, of course people notice it when a giant company releases something new and both Go and Lua are very popular. Quote:
Eventually we will add more documentation to the README. We honestly didn't think people would discover (let alone use) this project the day we open-sourced it. So it's been a pleasant surprise, but one that caught us off guard.
Why is Microsoft even doing this you might ask, and why do they use Google's Go language for the implementation and not for example Rust? Microsoft apparently wants to use it as an embedded language in Helm, which is written in Go.