When Turbo is detected during build, output directory no longer falls back to `.` if `public` does not exist

[unitof]

When Turbo is detected during build, output directory no longer falls back to `.` if `public` does not exist

[unitof]

Note that overriding the outputDirectory to . also works, when Turbo is detected.

[anthonyshew]

Just looking quickly I see a few problems:

1. This turbo.json doesn't cache anything. You need an outputs key so that turbo knows what to restore from cache if/when it hits cache.
2. In your issue you wrote "Deploy it to Vercel with a root directory of ./apps/static-html" - but I don't see a directory of ./apps/static-html in your repository. Was this a typo and you meant ./apps/static-site? That directory is in the repository. If a Root Directory is set that isn't there, I would expect problems. 😄