Generics require go 1.18

[asmaloney]

No description provided.

[bbredesen]

I see no issue w/ the update to 1.18 and will merge this in, but it's worth noting that it isn't strictly necessary for vk-gen.

The only use of generics is in static_include/static_mem.go. gopls will complain about that file, but it is only embedded in the output and not actually compiled as part of vk-gen. (1.18+ is of course required for go-vk though, because it does compile in those generic functions.)

I use VS Code and added the following to my settings.json, I presume a similar mechanism is available in most editors.

    "gopls": {
        "directoryFilters": [
            "-static_include"
        ],
    }