fix: astro default options

Author: yjl9903

src/astro.ts

@@ -2,7 +2,7 @@ import type { Options } from './core';
 
 import VitePlugin from './vite';
 
-export default (options: Options | undefined) => ({
+export default (options: Options = {}) => ({
   name: 'unplugin-info',
   hooks: {
     'astro:config:setup': async (astro: any) => {