fix head.tsx

Jacky Zhao

2023-08-09 ee9ed4f2877bff1a64104b6d97ed0d51b1bb6fa3

 content/migrating from Quartz 3.md

@@ -6,6 +6,7 @@

```bash
git checkout v4-alpha
git pull upstream v4-alpha
npm i
npx quartz create
```