Added NeurIPS-21 paper on Safe RL (IBM, Tshinghua) (#161)

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):
+- [Safe Policy Optimization with Local Generalized Linear Function Approximations](https://arxiv.org/abs/2111.04894) (IBM Research, Tsinghua University, NeurIPS 2021)
 - [A Consciousness-Inspired Planning Agent for Model-Based Reinforcement Learning](https://arxiv.org/abs/2106.02097) (Mila, McGill University, 2021)
 - [SPOTTER: Extending Symbolic Planning Operators through Targeted Reinforcement Learning](http://www.ifaamas.org/Proceedings/aamas2021/pdfs/p1118.pdf) (Tufts University, SIFT, AAMAS 2021)
 - [Grid-to-Graph: Flexible Spatial Relational Inductive Biases for Reinforcement Learning](https://arxiv.org/abs/2102.04220) (UCL, AAMAS 2021)