Add robotics task category to dataset card

This PR adds the `robotics` task category to the dataset card.

README.md

@@ -1 +1,8 @@
-arxiv: https://arxiv.org/abs/2506.07961
+---
+task_categories:
+- robotics
+---
+
+arxiv: https://arxiv.org/abs/2506.07961
+
+Project Website: https://bridgevla.github.io/