added flutter-tools plugin with lsp setup

lua/custom/plugins/flutter-tools.lua

@@ -0,0 +1,25 @@
+-- FLUTTER TOOLS
+return {
+	'akinsho/flutter-tools.nvim',
+	lazy = false,
+
+	dependencies = {
+		'nvim-lua/plenary.nvim',
+		'stevearc/dressing.nvim', -- optional for vim.ui.select
+	},
+
+	config = function()
+		require("flutter-tools").setup {
+			dev_log = {
+				enabled = true,
+				notify_errors = true, -- if there is an error whilst running then notify the user
+				open_cmd = "tabedit", -- command to use to open the log buffer
+			},
+
+			lsp = {
+				on_attach = require('custom.utils'),
+			}
+		} -- use default
+		require("telescope").load_extension("flutter")
+	end,
+}