Update README.md to include Flux-Fast (#2457)

Author: sayakpaul

README.md

@@ -60,7 +60,7 @@ Check out our [docs](https://docs.pytorch.org/ao/main/) for more details!
 From the team that brought you the fast series:
 * 9.5x inference speedups for Image segmentation models with [sam-fast](https://pytorch.org/blog/accelerating-generative-ai)
 * 10x inference speedups for Language models with [gpt-fast](https://pytorch.org/blog/accelerating-generative-ai-2)
-* 3x inference speedup for Diffusion models with [sd-fast](https://pytorch.org/blog/accelerating-generative-ai-3)
+* 3x inference speedup for Diffusion models with [sd-fast](https://pytorch.org/blog/accelerating-generative-ai-3) (new: [flux-fast](https://pytorch.org/blog/presenting-flux-fast-making-flux-go-brrr-on-h100s/))
 * 2.7x inference speedup for FAIR’s Seamless M4T-v2 model with [seamlessv2-fast](https://pytorch.org/blog/accelerating-generative-ai-4/)