feat: add notification about available new version (#853)

Co-authored-by: Anton Kozachuk <antonkozachuk@Antons-MacBook-Pro.local>

packages/cli/src/utils.ts

@@ -16,6 +16,7 @@ import {
   stringifyYaml,
 } from '@redocly/openapi-core';
 import { Totals, outputExtensions, Entrypoint } from './types';
+import * as updateNotifier from 'update-notifier';
 
 export async function getFallbackApisOrExit(
   argsApis: string[] | undefined,
@@ -323,3 +324,16 @@ export function isSubdir(parent: string, dir: string): boolean {
   const relative = path.relative(parent, dir);
   return !!relative && !/^..($|\/)/.test(relative) && !path.isAbsolute(relative);
 }
+
+export function notifyUpdateCliVersion() {
+  const pkg = require('../package.json');
+  const notifier = updateNotifier({
+    pkg,
+    updateCheckInterval: 0,
+    shouldNotifyInNpmScript: true,
+  });
+  notifier.notify({
+    message:
+      'A new version of Redocly CLI ({latestVersion}) is available.\nUpdate now: `npx @redocly/cli@latest upgrade`.\nChangelog: https://redocly.com/docs/cli/changelog',
+  });
+}