`govulncheck` reports error

The following message appeared when I ran `govulncheck`:

```
internal error: package "golang.org/x/sync/semaphore" without types was imported from "github.com/jackc/puddle/v2"
```

Start by reproducing the reported `govulncheck` failure in the puddle repository and inspect the dependency path from `github.com/jackc/puddle/v2` to `golang.org/x/sync/semaphore`. Confirm the relevant dependency and tooling versions, then define done as `govulncheck` completing without the reported internal error.

Written by the indexing model from the issue text.