(babel plugin) SyntaxError:Unexpected token

with babel plugins, It throwed a Error when I import _less_ to my js.

```shell
[!] (babel plugin) SyntaxError: /Users/**/lib-cli/src/style.less: Unexpected token (1:0)
src/style.less (1:0)
SyntaxError: /Users/**/lib-cli/src/style.less: Unexpected token (1:0)
> 1 | @black: #000000;
| ^
2 | .test{
3 | color: @black;
4 | background: @black;
```

index.js
```js
import './style.less';
```
rollup.config.js

```js
export default {
...
plugins:[{
babel({
runtimeHelpers: true,
exclude: 'node_modules/**'
}),
postcss({
extract: `dist/${name}.css`,
extensions: ['.less'],
plugins: [],
}),
}]
...
}
```
I find a way to resolve this problems by Add **babel.include**.
```js
export default {
...
plugins:[{
babel({
include: 'src/**/*.js',
runtimeHelpers: true,
exclude: 'node_modules/**'
}),
postcss({
extract: `dist/${name}.css`,
extensions: ['.less'],
plugins: [],
}),
}]
...
}
```