docs(deployment): heroku with nginx

[adetayoadeyemi]

…nx buildpack, a Nitro plugin and the node preset

🔗 Linked issue

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

The update documents setting up nginx on heroku
With this change, setting up nuxt on heroku with Nginx is straight forward, the update also explains how to use Nginx to server static files, this is a question that has been repeated a number of times on the Discord channel

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

[pi0]

Thanks! I've made a followup issue to possibly make a dedicated preset too if we can #876