docs: update readme

Signed-off-by: Ryan Wang <i@ryanc.cc>

README.md

@@ -19,6 +19,7 @@
 ## 开发环境运行
 
 ```bash
+# pnpm@7.0.0+
 npm install -g pnpm
 ```
 
@@ -26,6 +27,11 @@ npm install -g pnpm
 pnpm install 
 ```
 
+```bash
+# build packages
+pnpm build:packages
+```
+
 ```bash
 pnpm dev
 ```