go clean -modcache
go install github.com/lasorda/protobuf-language-server@latest

    "languageserver": {
        "proto" :{
            "command": "protobuf-language-server",
            "filetypes": ["proto", "cpp"]
            "settings": {
                "additional-proto-dirs": [ ]
            }
        }
    }

-- first we need to configure our custom server
local configs = require('lspconfig.configs')
local util = require('lspconfig.util')

configs.protobuf-language-server = {
    default_config = {
        cmd = { 'path/to/protobuf-language-server' },
        filetypes = { 'proto', 'cpp' },
        root_fir = util.root_pattern('.git'),
        single_file_support = true,
        settings = {
            ["additional-proto-dirs"] = [
                -- path to additional protobuf directories
                -- "vendor",
                -- "third_party",
            ]
        },
    }
}

-- then we can continue as we do with official servers
local lspconfig = require('lspconfig')
lspconfig.protobuf-language-server.setup {}