Update NEWS.md
Change news date for Personality-Captions model release
## News
-2019-05-31: The [Personality-Captions project page](http://parl.ai/projects/personality_captions/) is updated with pretrained models, specialized model code, and an interactive demo.
+2019-06-12: The [Personality-Captions project page](http://parl.ai/projects/personality_captions/) is updated with pretrained models, specialized model code, and an interactive demo.
2019-06-12: Added [HotpotQA](https://github.com/facebookresearch/ParlAI/tree/master/parlai/tasks/quac) as another dataset.
