Add dataset card, link to paper and Github repo

This PR adds the dataset card, ensures the dataset can be found at https://huggingface.co/papers/2505.13938 and links to the github repository.

README.md

@@ -1,3 +1,9 @@
----
-license: mit
----
+---
+license: mit
+task_categories:
+- text-generation
+---
+
+This repository contains the data for the paper [CLEVER: A Curated Benchmark for Formally Verified Code Generation](https://huggingface.co/papers/2505.13938).
+
+The benchmark can be found on GitHub: https://github.com/trishullab/clever