doc: update README.md

Author: AntoineGS

README.md

@@ -158,7 +158,7 @@ require('copilot').setup({
   },
   copilot_node_command = 'node', -- Node.js version must be > 20
   workspace_folders = {},
-  copilot_model = "",  -- Current LSP default is gpt-35-turbo, supports gpt-4o-copilot
+  copilot_model = "",
   root_dir = function()
     return vim.fs.dirname(vim.fs.find(".git", { upward = true })[1])
   end,