docs: revert cdn URL (#8310)

src/toast/README.md

@@ -44,7 +44,7 @@ Toast({
 
 Toast({
   message: 'Custom Image',
-  icon: 'https://img01.yzcdn.cn/vant/logo.png',
+  icon: 'https://img.yzcdn.cn/vant/logo.png',
 });
 
 Toast.loading({

src/toast/README.zh-CN.md

@@ -54,7 +54,7 @@ Toast({
 
 Toast({
   message: '自定义图片',
-  icon: 'https://img01.yzcdn.cn/vant/logo.png',
+  icon: 'https://img.yzcdn.cn/vant/logo.png',
 });
 
 Toast.loading({

src/toast/demo/index.vue

@@ -118,7 +118,7 @@ export default {
     const showImageToast = () => {
       Toast({
         message: t('customImage'),
-        icon: 'https://img01.yzcdn.cn/vant/logo.png',
+        icon: 'https://img.yzcdn.cn/vant/logo.png',
       });
     };