[ci skip] docs: fix Nuxt badge icon

[IO-Fire]

🔗 Linked issue

https://github.com/nuxt/starter/issues/1659

❓ Type of change

• [x] 📖 Documentation (updates to the documentation or readme)
• [ ] 🐞 Bug fix (a non-breaking change that fixes an issue)
• [ ] 👌 Enhancement (improving an existing functionality)
• [ ] ✨ New feature (a non-breaking change that adds functionality)
• [ ] 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• [ ] ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

The Nuxt logo is missing from Nuxt badge in the README.md.

->

See original issue from the module template for more details.