Placeholder setting doesn't work

Hi,
I want to change the default text "Type text..." but for some reason `placeholder` argument for EditorJsJSONField field doesn't change anything. My code:

```
class Page(models.Model):
    ...
    content = EditorJsJSONField(
        "Content",
        blank=True,
        null=True,
        placeholder="Write your post content here...")
```

What I'm doing wrong?