Add library name and pipeline tag; link to Github

This PR adds the `library_name` and `pipeline_tag` metadata to the model card.
It also adds a link to the Github repository.

README.md

@@ -1,3 +1,9 @@
----
-license: apache-2.0
----
+---
+license: apache-2.0
+library_name: transformers
+pipeline_tag: robotics
+---
+
+This repository contains the model described in [WorldVLA: Towards Autoregressive Action World Model](https://huggingface.co/papers/2506.21539).
+
+Code: https://github.com/alibaba-damo-academy/WorldVLA