How to add custom lang server without fork and send a PR to nvim-lspconfig repo? [resolved]

I have a nomadls.lua like this:

local configs = require "lspconfig/configs"
local util = require "lspconfig/util"

configs.nomadls = {
    default_config = {
        cmd = { "nomad-lsp" },
        filetypes = { "nomad" },
        root_dir = util.path.dirname,
    },
    -- on_new_config = function(new_config) end;
    -- on_attach = function(client, bufnr) end;
    docs = {
        description = [[
https://github.com/ttys3/nomad-lsp
Language Server Protocol for Nomad.
]],
        default_config = {
            root_dir = [[root_pattern(".git")]],
        },
    },
}
-- vim:et ts=2 sw=2

and the config

require "lsp.nomadls"

local lsp = require "lspconfig"

lsp.nomadls.setup {}

but the problem is, the lang server nerver start.

(if I use my own fork of nvim-lspconfig repo, it works fine).

after update to latest nightly version.

now it works.

NVIM v0.6.0-dev+340-g7cb34a341
Build type: RelWithDebInfo
LuaJIT 2.1.0-beta3

This is really useful to have as an example, thanks for posting and good to know it works in 0.6.