feat: allow peerDeps as import entry points

[beerose]

PR context

Let's say I have next in peerDependencies, and the following import in my package:

import something from "next/head"

When building the package with unbuild, it shows a warning: Potential implicit dependencies found: next/head, while I think it should be legal to use import from peerDeps.

Let me know if I should make any changes.

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Thank you for building unbuild 🔥

[pi0]

Thanks!