Postgres `sql` command using fetch but not exposing options

The sql template literal uses @neondatabase/serverless, which uses fetch. When using this function in Next.js, this causes the result to be automatically cached.

As this function does not expose the fetch options, it is only possible to set them per rout not per-request. This means that (as far as I'm aware) you:

1. Cannot set tags to allow the use of revalidateTag
2. Cannot have different revalidation conditions for different requests on the same page (e.g. revalidate a list of comments more often than a blog post)

The neon functions called allow you to pass fetch options, but this library does not (as far as I can tell) provide a way for a developer to provide them.

I created an example of how these options could be passed here. In this example you would have the option of replacing db.sql'...' with db.withFetchOptions(...).sql'...' to set the options used by fetch without altering the behaviour of the original.

Start at the sql template literal integration with @neondatabase/serverless and compare it with the linked vercel-storage example using withFetchOptions. Confirm how fetch options can be exposed per request without changing existing behavior, and verify that callers can set tags and different revalidation conditions for separate queries.