adds license information for DailyDialog.
Thanks! Can you also add it as metadata in the YAML block at the top of the file?

Should be in the form:

```
licenses:
- cc-by-sa-4.0
``` seems like we need to add all the other tags ? 
```       
if error_messages:
>           raise ValueError("\n".join(error_messages))
E           ValueError: The following issues have been found in the dataset cards:
E           YAML tags:
E           __init__() missing 8 required positional arguments: 'annotations_creators', 'language_creators', 'languages', 'multilinguality', 'size_categories', 'source_datasets', 'task_categories', and 'task_ids'
``` I'll let @lhoestq or @yjernite chime in (and maybe complete/merge). Thanks! Looks like CircleCI has an incident. Let's wait for it to be working again and make sure the CI is green The remaining error is unrelated to this PR, merging