fix issue#6

Author: haorenW1025

lua/diagnostic.lua

@@ -1,5 +1,5 @@
 local vim = vim
-local util = require 'util'
+local util = require 'diagnostic.util'
 local M = {}
 
 M.bufferDiagnostic = {}

lua/util.lua lua/diagnostic/util.lualua/util.lua renamed to lua/diagnostic/util.lua

@@ -1,6 +1,6 @@
 local vim = vim
 local api = vim.api
-local util = require'util'
+local util = require'diagnostic.util'
 local diagnostic = require'diagnostic'
 local M = {}