support Lua 5.4

[Alloyed]

Ideally, we should update our grammar to support the new features at the same time that we port to lua 5.4 as a runtime

https://www.lua.org/versions.html

[Alloyed]

lua 5.4 is passing our unit tests as of 52e69dc
still on the dev branch but I'll close this bug once it's on master and I can tag a release with it

[Sunspar]

Any idea when a version bump might be planned to resolve this? I run CoC's lua plugin and it would be nice to be able to get rid of my separate Lua 5.3.5 install as it's only around in order to get things to play nicely with lua-lsp.

[hungrybirder]

HI, Any progess on this issue?

[AdamBD]

also looking for this for 5.4 if possible

[erf]

Would like to have 5.4 supported for use with: https://github.com/fischerling/vis-lspc/