Update README.md (#41959)

Yarn command has been updated on README.md

examples/with-turbopack/README.md

@@ -14,7 +14,7 @@ This playground is a mirror of the [Next.js v13 App Directory Playground](https:
 **Note:** The playground uses [Tailwind CSS](https://tailwindcss.com). However, Turbopack does not yet support fully [PostCSS](https://turbo.build/pack/docs/features/css#postcss), but it does support CSS and CSS Modules. [As a workaround](https://turbo.build/pack/docs/features/css#tailwind-css), we run Tailwind through it's CLI upon `postinstall`. For live reload of CSS, you can run Tailwind in another process with the `--watch` flag or install `concurrently` and modify your `dev` script:
 
 ```bash
-yarn install concurrently --dev
+yarn add concurrently --dev
 ```
 
 Then modify your `dev` script in `package.json`: