Update README.md

README.md

 # NerfAcc
 [![Core Tests.](https://github.com/KAIR-BAIR/nerfacc/actions/workflows/code_checks.yml/badge.svg)](https://github.com/KAIR-BAIR/nerfacc/actions/workflows/code_checks.yml)
 [![Documentation Status](https://readthedocs.com/projects/plenoptix-nerfacc/badge/?version=latest)](https://www.nerfacc.com/en/latest/?badge=latest)
+[![Downloads](https://pepy.tech/badge/nerfacc)](https://pepy.tech/project/nerfacc)
 
 https://www.nerfacc.com/
 
@@ -132,4 +133,4 @@ python examples/train_ngp_nerf.py --train_split train --scene garden --auto_aabb
   journal={arXiv preprint arXiv:2210.04847},
   year={2022}
 }
-```
\ No newline at end of file
+```