feat(nx): update nx example with vercel.json (#1066)

### Description

Update nx example to demonstrate configuration for vercel.json

### Demo URL

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Provide a URL to a live deployment where we can test your PR. If a demo
isn't possible feel free to omit this section.
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### Type of Change

- [ ] New Example
- [ ] Example updates (Bug fixes, new features, etc.)
- [ ] Other (changes to the codebase, but not to examples)

### New Example Checklist

- [ ] 🛫 `npm run new-example` was used to create the example
- [ ] 📚 The template wasn't used but I carefuly read the [Adding a new
example](https://github.com/vercel/examples#adding-a-new-example) steps
and implemented them in the example
- [ ] 📱 Is it responsive? Are mobile and tablets considered?

Author: tknickman

solutions/nx-monorepo/README.md

@@ -5,7 +5,7 @@ description: Learn to implement a monorepo with a single Next.js site using Nx.
 framework: Next.js
 useCase: Documentation
 css: CSS
-deployUrl: https://vercel.com/new/clone?repository-url=https://github.com/vercel/examples/tree/main/solutions/nx-monorepo&project-name=nx-monorepo&output-directory=dist%2Fapps%2Fapp%2F.next&build-command=npx%20nx%20build%20app%20--prod&repository-name=nx-monorepo
+deployUrl: https://vercel.com/new/clone?repository-url=https%3A%2F%2Fgithub.com%2Fvercel%2Fexamples%2Ftree%2Fmain%2Fsolutions%2Fnx-monorepo&project-name=nx-monorepo&output-directory=out%2F.next&build-command=cd+..%2F..%2F+%26%26+npx+nx+build+app+--prod&repository-name=nx-monorepo&root-directory=apps%2Fapp
 relatedTemplates:
   - monorepo-turborepo
   - turborepo-next-basic

solutions/nx-monorepo/apps/app/project.json

@@ -9,7 +9,7 @@
       "defaultConfiguration": "production",
       "options": {
         "root": "apps/app",
-        "outputPath": "dist/apps/app"
+        "outputPath": "apps/app/out"
       },
       "configurations": {
         "development": {

solutions/nx-monorepo/apps/app/vercel.json

@@ -0,0 +1,3 @@
+{
+  "framework": "nextjs"
+}