How to bundle dependencies?

Hi, I've got following `tsup.config.ts`:

```ts
import type { Options } from 'tsup';

const env = process.env.NODE_ENV;

export const tsup: Options = {
bundle: true,
skipNodeModulesBundle: false,
};
```

when running `npx tsup src/runtime-libs/runtime-libs.ts --out-dir test --platform=browser`

I can still see in my generated code `__toESM(require("spectorjs")`. I want `sup` to bundle all dependencies, just like `rebuild --bundle` does. How can I achieve it?

Start with tsup.config.ts and the src/runtime-libs/runtime-libs.ts entry point, then run the reported npx tsup command with the shown browser platform and output directory. Compare the generated code with the expected bundled output and verify whether the spectorjs dependency is still emitted as require("spectorjs").

Written by the indexing model from the issue text.