Generated possible types missing correct indentation

**Describe the bug**
Generating an empty possible types file
```js

export interface PossibleTypesResultData {
possibleTypes: {
[key: string]: string[]
}
}
const result: PossibleTypesResultData = {
"possibleTypes": {}
};
export default result;

```

**To Reproduce**
Steps to reproduce the behavior:

3. My `codegen.yml` config file:

```yaml
overwrite: true
schema: 'http://localhost:3000/graphql'
documents: ./src/graphql/**/*.ts
generates:
src/types/graphql-generated.ts:
plugins:
- 'fragment-matcher'
```

**Expected behavior**

The code should be indented properly