Fix broken link in README.md
Summary:
is not longer valid, redirects to a blog post listing page.
Pull Request resolved:
@@ -4,7 +4,7 @@ These scripts provide an example of pre-processing data for the Language Modelin
# prepare-wikitext-103.sh
-Provides an example of pre-processing for [WikiText-103 language modeling task](https://einstein.ai/research/the-wikitext-long-term-dependency-language-modeling-dataset):
+Provides an example of pre-processing for [WikiText-103 language modeling task](https://www.salesforce.com/products/einstein/ai-research/the-wikitext-dependency-language-modeling-dataset/):
Example usage:
```
