Fix arxiv link

Current link tries to point to relative directory new link points to full URL.

README.md

@@ -145,7 +145,7 @@ Meta developed and publicly released the Llama 2 family of large language models
 
 **License** A custom commercial license is available at: [https://ai.meta.com/resources/models-and-libraries/llama-downloads/](https://ai.meta.com/resources/models-and-libraries/llama-downloads/)
 
-**Research Paper** ["Llama-2: Open Foundation and Fine-tuned Chat Models"](arxiv.org/abs/2307.09288)
+**Research Paper** ["Llama-2: Open Foundation and Fine-tuned Chat Models"](https://arxiv.org/abs/2307.09288)
 
 ## Intended Use
 **Intended Use Cases** Llama 2 is intended for commercial and research use in English. Tuned models are intended for assistant-like chat, whereas pretrained models can be adapted for a variety of natural language generation tasks.