Add yarn scripts

packages/create-next-app/templates/default/README-template.md

@@ -57,20 +57,20 @@ Read more about [Next's Routing](https://nextjs.org/docs/routing/introduction)
 
 In the project directory, you can run:
 
-### `npm run dev`
+### `npm run dev` (or `yarn dev`)
 
 Runs the app in the development mode.<br>
 Open [http://localhost:3000](http://localhost:3000) to view it in the browser.
 
 The page will reload if you make edits.<br>
 You will also see any errors in the console.
 
-### `npm run build`
+### `npm run build` (or `yarn build`)
 
 Builds the app for production to the `.next` folder.<br>
 It correctly bundles React in production mode and optimizes the build for the best performance.
 
-### `npm run start`
+### `npm run start` (or `yarn start`)
 
 Starts the application in production mode.
 The application should be compiled with \`next build\` first.