Add project name to examples/with-three-js create command (vercel#17256)

This is a change to add the project name as in the other examples.
When we run with the current create command, we are asked for the project name.
As follows:

```
$ npx create-next-app --example with-three-js
? What is your project named? › my-app
```

examples/with-three-js/README.md

@@ -17,9 +17,9 @@ Deploy the example using [Vercel](https://vercel.com):
 Execute [`create-next-app`](https://github.com/vercel/next.js/tree/canary/packages/create-next-app) with [npm](https://docs.npmjs.com/cli/init) or [Yarn](https://yarnpkg.com/lang/en/docs/cli/create/) to bootstrap the example:
 
 ```bash
-npx create-next-app --example with-three-js
+npx create-next-app --example with-three-js with-three-js-app
 # or
-yarn create next-app --example with-three-js
+yarn create next-app --example with-three-js with-three-js-app
 ```
 
 Deploy it to the cloud with [Vercel](https://vercel.com/import?filter=next.js&utm_source=github&utm_medium=readme&utm_campaign=next-example) ([Documentation](https://nextjs.org/docs/deployment)).