[doc] Fix the link to the QuanTaichi paper in README.md

README.md

@@ -70,7 +70,7 @@ If you use Taichi in your research, please cite related papers:
 
 - [**(SIGGRAPH Asia 2019) Taichi: High-Performance Computation on Sparse Data Structures**](https://yuanming.taichi.graphics/publication/2019-taichi/taichi-lang.pdf) [[Video]](https://youtu.be/wKw8LMF3Djo) [[BibTex]](https://raw.githubusercontent.com/taichi-dev/taichi/master/misc/taichi_bibtex.txt) [[Code]](https://github.com/taichi-dev/taichi)
 - [**(ICLR 2020) DiffTaichi: Differentiable Programming for Physical Simulation**](https://arxiv.org/abs/1910.00935) [[Video]](https://www.youtube.com/watch?v=Z1xvAZve9aE) [[BibTex]](https://raw.githubusercontent.com/taichi-dev/taichi/master/misc/difftaichi_bibtex.txt) [[Code]](https://github.com/yuanming-hu/difftaichi)
-- [**(SIGGRAPH 2021) QuanTaichi: A Compiler for Quantized Simulations**](https://yuanming.taichi.graphics/publication/2019-taichi/taichi-lang.pdf) [[Video]](https://www.youtube.com/watch?v=0jdrAQOxJlY) [[BibTex]](https://raw.githubusercontent.com/taichi-dev/taichi/master/misc/quantaichi_bibtex.txt) [[Code]](https://github.com/taichi-dev/quantaichi)
+- [**(SIGGRAPH 2021) QuanTaichi: A Compiler for Quantized Simulations**](https://yuanming.taichi.graphics/publication/2021-quantaichi/quantaichi.pdf) [[Video]](https://www.youtube.com/watch?v=0jdrAQOxJlY) [[BibTex]](https://raw.githubusercontent.com/taichi-dev/taichi/master/misc/quantaichi_bibtex.txt) [[Code]](https://github.com/taichi-dev/quantaichi)
 
 ## Links
 - [TaichiCon](https://github.com/taichi-dev/taichicon): Taichi developer conferences.