feat: warn about requirement of 0.11+ coming up

fixes #555

Author: AntoineGS

lua/copilot/init.lua

@@ -5,6 +5,14 @@ local client = require("copilot.client")
 local config = require("copilot.config")
 
 M.setup = function(opts)
+  if vim.fn.has("nvim-0.11") == 0 then
+    vim.notify_once(
+      "[copilot.lua] Neovim 0.11+ will soon be required. Please upgrade your Neovim version if you wish to keep using this plugin.",
+      vim.log.levels.WARN
+    )
+    return
+  end
+
   if M.setup_done then
     return
   end