Fix arxiv link (#2)

- Fix arxiv link (ba55983c018ea882f4ce41e73ee8d58853daec7b)
- Replace arxiv link to abstract (c0e754b2495d2bc7d6e04677425b2de5f49b7983)


Co-authored-by: Loïck BOURDOIS <[email protected]>

README.md

@@ -786,7 +786,7 @@ dataset_info:
 ## Dataset Description
 
 - **Homepage:** [XGLUE homepage](https://microsoft.github.io/XGLUE/)
-- **Paper:** [XGLUE: A New Benchmark Dataset for Cross-lingual Pre-training, Understanding and Generation](https://arxiv.org/abs/1907.09190)
+- **Paper:** [XGLUE: A New Benchmark Dataset for Cross-lingual Pre-training, Understanding and Generation](https://arxiv.org/abs/2004.01401)
 
 ### Dataset Summary