Update README.md (#116)

* Update README.md

Adding link to AIS paper

* Update README.md

Co-authored-by: Maxime Chevalier-Boisvert <maximechevalierb@gmail.com>

README.md

@@ -29,6 +29,7 @@ Please use this bibtex if you want to cite this repository in your publications:
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 List of publications & submissions using MiniGrid or BabyAI (please open a pull request to add missing entries):
+- [Approximate Information State for Approximate Planning and Reinforcement Learning in Partially Observed Systems](https://arxiv.org/abs/2010.08843) (McGill, October 2020)
 - [Prioritized Level Replay](https://arxiv.org/pdf/2010.03934.pdf) (FAIR, October 2020)
 - [Learning with AMIGO: Adversarially Motivated Intrinsic Goals](https://arxiv.org/pdf/2006.12122.pdf) (MIT, FAIR, June 2020)
 - [RIDE: Rewarding Impact-Driven Exploration for Procedurally-Generated Environments](https://openreview.net/forum?id=rkg-TJBFPB) (FAIR, ICLR 2020)