How to make less and modules work together?

As my understanding from the README, I just need to install the `less` as the dependency and set `modules: true` then I can import less file as css modules like this:

```
// MyComponent.tsx
import styles from "./MyComponent.less"
```

But I get the errror: `[!] (rpt2 plugin) Error: ... semantic error TS2307 Cannot find module './MyComponent.less'` after running the `rollup -c`.

I use the rollup-plugin-css version 1.6.2 and rollup version 0.62.0

My rollup.config.js:

```
...
plugins: [
external(),
postcss({
modules: true
}),
...
```