Add Phi4 to README.md (#2383)

Author: krammnic

README.md

@@ -52,6 +52,7 @@ torchtune currently supports the following models.
 | [Gemma](https://huggingface.co/collections/google/gemma-release-65d5efbccdbb8c4202ec078b)   | 2B, 7B [[models](torchtune/models/gemma/_model_builders.py), [configs](recipes/configs/gemma/)] |
 | [Gemma2](https://huggingface.co/docs/transformers/main/en/model_doc/gemma2)   | 2B, 9B, 27B [[models](torchtune/models/gemma2/_model_builders.py), [configs](recipes/configs/gemma2/)] |
 | [Microsoft Phi3](https://huggingface.co/collections/microsoft/phi-3-6626e15e9585a200d2d761e3) | Mini [[models](torchtune/models/phi3/), [configs](recipes/configs/phi3/)]
+| [Microsoft Phi4](https://huggingface.co/collections/microsoft/phi-4-677e9380e514feb5577a40e4) | 14B [[models](torchtune/models/phi4/), [configs](recipes/configs/phi4/)]
 | [Qwen2](https://qwenlm.github.io/blog/qwen2/) | 0.5B, 1.5B, 7B [[models](torchtune/models/qwen2/), [configs](recipes/configs/qwen2/)]
 | [Qwen2.5](https://qwenlm.github.io/blog/qwen2.5/) | 0.5B, 1.5B, 3B, 7B, 14B, 32B, 72B [[models](torchtune/models/qwen2_5/), [configs](recipes/configs/qwen2_5/)]