chore: added npm package entry file

Author: anlyyao

src/index.ts

@@ -0,0 +1,3 @@
+export { default as Dialog } from './dialog/index';
+export { default as Message } from './message/index';
+export { default as Toast } from './toast/index';

src/toast/_example/base/index.js

@@ -1,6 +1,6 @@
 import SkylineBehavior from '@behaviors/skyline.js';
 
-import Toast from 'tdesign-miniprogram/toast/index';
+import { Toast } from 'tdesign-miniprogram';
 
 Component({
   behaviors: [SkylineBehavior],