Add missing metadata and improve model card

This PR adds missing metadata to the model card, including the `pipeline_tag` and `license`. This improves discoverability and clarity for users. The `pipeline_tag` is set to `feature-extraction` as FlashNorm is a faster implementation of RMSNorm, commonly used for this purpose in LLMs. It also adds a link to the code.

README.md

@@ -1,8 +1,12 @@
 ---
 language:
 - en
+pipeline_tag: feature-extraction
+license: mit
 ---
+
 This repo contains code and links for the [Flash normalization paper](https://arxiv.org/abs/2407.09577):
 * <a href="https://colab.research.google.com/github/OpenMachine-ai/transformer-tricks/blob/main/flash_normalization.ipynb"><img src="https://colab.research.google.com/assets/colab-badge.svg" alt="Colab" height="20"></a>
 * Paper: [arXiv](https://arxiv.org/abs/2407.09577), [HuggingFace paper page](https://huggingface.co/papers/2407.09577), and [latex](https://github.com/OpenMachine-ai/transformer-tricks/blob/main/latex/flash.tex)
+* Code: https://github.com/OpenMachine-ai/transformer-tricks
 * See [here](https://github.com/OpenMachine-ai/transformer-tricks/tree/main) for more transformer tricks