chore: update readme

Author: litingyes

README.md

@@ -22,7 +22,7 @@ A Vite plugin made for previewing and editing Vue components in Markdown and, of
 ## Install
 
 ```bash
-pnpm add vite-plugin-vue-preview
+pnpm add vite-plugin-vue-preview@1
 ```
 
 ## Features

README.zh-CN.md

@@ -22,7 +22,7 @@
 ## 安装
 
 ```bash
-pnpm add vite-plugin-vue-preview
+pnpm add vite-plugin-vue-preview@1
 ```
 
 ## 特征

test/vitepress/index.md

@@ -27,7 +27,7 @@ import { isSpecialBooleanAttr } from '@vue/shared'
 ## Install
 
 ```bash
-pnpm add vite-plugin-vue-preview
+pnpm add vite-plugin-vue-preview@1
 ```
 
 ## Features

test/vitepress/zh/index.md

@@ -27,7 +27,7 @@ import { isSpecialBooleanAttr } from '@vue/shared'
 ## 安装
 
 ```bash
-pnpm add vite-plugin-vue-preview
+pnpm add vite-plugin-vue-preview@1
 ```
 
 ## 特征