docs: make readme alpha ready

README.md

@@ -1,4 +1,4 @@
-# (WIP) VitePress 📝💨
+# VitePress (alpha) 📝💨
 
 [![Test](https://github.com/vuejs/vitepress/workflows/Test/badge.svg)](https://github.com/vuejs/vitepress/actions)
 [![npm](https://img.shields.io/npm/v/vitepress)](https://www.npmjs.com/package/vitepress)
@@ -7,6 +7,8 @@
 
 VitePress is [VuePress](https://vuepress.vuejs.org)' spiritual successor, built on top of [vite](https://github.com/vitejs/vite).
 
+Currently, it's in the `alpha` stage. It is already suitable for out-of-the-box documentation use, but the config and theming API may still change between minor releases.
+
 ## Documentation
 
 To check out docs, visit [vitepress.vuejs.org](https://vitepress.vuejs.org).

docs/guide/getting-started.md

@@ -2,6 +2,10 @@
 
 This section will help you build a basic VitePress documentation site from ground up. If you already have an existing project and would like to keep documentation inside the project, start from Step 3.
 
+::: warning
+VitePress is currently in `alpha` status. It is already suitable for out-of-the-box documentation use, but the config and theming API may still change between minor releases.
+:::
+
 ## Step. 1
 
 Create and change into a new directory.