Test with Lua 5.4 so we're ready when it's released

[alerque]

A beta release of Lua 5.4.0 has been announced.

• Add it to our CI workflow so we know what's going on with it (as allow-fail)
• Fix anything that doesn't run on it properly so there are no hiccups when it's released and people start having it show up as the Lua interpreter on their systems.
• When we pass out tests on it, start making them required for new development work.

See also #606 for LuaJIT.

[alerque]

http://www.lua.org/versions.html#5.4

It's out.

[alerque]

This is currently blocking on lua-luaepnf/issues/4 at the least, possibly more...

[alerque]

Luaepnf solved with upstream release.

We're now hung up on bit32.

[alerque]

Looks like compat53 just got released which hopefully means a release for bit32 support is in the works.

[alerque]

Next up we're going to be stuck on lua-zlib.

[alerque]

That looks like the lot of them. Unfortunately lua-zlib isn't well maintained, we make have to fork that to get it up to speed. Also not up to speed with Lua 5.4 but if updating lua-zlib proves too painful we could look into lzlib.

[alerque]

That last PR took care of bit32, the final hold-out is lua-zlib. I've tested it with a fork and gotten it to work, but the upstream needs to release a new rockspec before we can reasonably start requiring it!