[Docs] Add a new ecosystem in README (#1296)

Author: zhouzaida

README.md

@@ -361,6 +361,7 @@ This project is released under the [Apache 2.0 license](LICENSE).
 ## Ecosystem
 
 - [APES: Attention-based Point Cloud Edge Sampling](https://github.com/JunweiZheng93/APES)
+- [DiffEngine: diffusers training toolbox with mmengine](https://github.com/okotaku/diffengine)
 
 ## Projects in OpenMMLab
 

README_zh-CN.md

@@ -362,6 +362,7 @@ runner.train()
 ## 生态项目
 
 - [APES: Attention-based Point Cloud Edge Sampling](https://github.com/JunweiZheng93/APES)
+- [DiffEngine: diffusers training toolbox with mmengine](https://github.com/okotaku/diffengine)
 
 ## OpenMMLab 的其他项目