Merge pull request google-research#158 from zhaoyongke/master

Fix squad 2.0 dev data link

README.md

@@ -449,7 +449,7 @@ To run on SQuAD 2.0, you will first need to download the dataset. The necessary
 files can be found here:
 
 *   [train-v2.0.json](https://rajpurkar.github.io/SQuAD-explorer/dataset/train-v2.0.json)
-*   [dev-v2.0.json](https://rajpurkar.github.io/SQuAD-explorer/dataset/dev-v1.1.json)
+*   [dev-v2.0.json](https://rajpurkar.github.io/SQuAD-explorer/dataset/dev-v2.0.json)
 *   [evaluate-v2.0.py](https://worksheets.codalab.org/rest/bundles/0x6b567e1cf2e041ec80d7098f031c5c9e/contents/blob/)
 
 Download these to some directory `$SQUAD_DIR`.