chore: add warning message

lua/Trans/core/conf.lua

@@ -6,6 +6,7 @@
 return {
     ---@type string the directory for database file and password file
     dir      = require 'Trans'.plugin_dir,
+    warning = true,
     debug    = true,
     ---@type 'default' | 'dracula' | 'tokyonight' global Trans theme [see lua/Trans/style/theme.lua]
     theme    = 'default', -- default | tokyonight | dracula

lua/Trans/core/setup.lua

@@ -52,4 +52,12 @@ return function(opts)
 
     set_strategy_opts(conf)
     define_highlights(conf)
+
+    if Trans.conf.warning then
+        vim.notify([[
+新版本v2已经发布, 见:
+    https://github.com/JuanZoran/Trans.nvim
+请使用当前默认(v2)分支
+        ]], vim.log.levels.WARN)
+    end
 end