Nextra can't start with turbopack

[pawelkrystkiewicz]

When trying to use with --turbo flag as per docs there is an error:

>$ next dev  --turbo
>>> TURBOPACK (alpha)

Thank you for trying Next.js v13 with Turbopack! As a reminder,
Turbopack is currently in alpha and not yet ready for production.
We appreciate your ongoing support as we work to make it ready
for everyone.

Warning: You are using configuration that may require additional
setup with Turbopack. If you already made these changes please
ignore this warning.

- PostCSS detected (postcss.config.js)
  PostCSS is not yet supported by Next.js v13 with Turbopack.
  To use with Turbopack, see: https://nextjs.link/turbopack-postcss

- Tailwind detected (tailwind.config.js)
  Tailwind is not yet supported by Next.js v13 with Turbopack.
  To use with Turbopack, see: https://nextjs.link/turbopack-tailwind

Error: You are using configuration and/or tools that are not yet
supported by Next.js v13 with Turbopack:


- Unsupported Next.js configuration option(s) (next.config.js)
  The only configurations options supported are:
    - experimental.serverComponentsExternalPackages
    - experimental.transpilePackages
  To use Turbopack, remove other configuration options.   

If you cannot make the changes above, but still want to try out
Next.js v13 with Turbopack, create the Next.js v13 playground app
by running the following commands:

  yarn create next-app --example with-turbopack with-turbopack-app
  cd with-turbopack-app
  yarn run dev
        
Learn more about Next.js v13 and Turbopack: https://nextjs.link/with-turbopack
Please direct feedback to: https://nextjs.link/turbopack-feedback

Versions

    "next": "13.0.6",
    "nextra": "^2.0.1",
    "nextra-theme-docs": "^2.0.1",
    "react": "18.2.0",
    "react-dom": "18.2.0",
    "typescript": "4.9.3"