Add support for workspace folders

[prabirshrestha]

Might be good to start with one of the server such as gopls.

let g:lsp_settings = {
      \ 'gopls': {
      \  'root_uri':{server_info->lsp#utils#path_to_uri(lsp#utils#find_nearest_parent_file_directory(lsp#utils#get_buffer_path(), 'go.mod'))},
      \  }
      \ }

More info at https://github.com/prabirshrestha/vim-lsp/pull/1265