Update Broken link (#10712)

Update 'nlp model building` broken link

README.md

@@ -43,7 +43,7 @@ pip3 install tf-models-official
 
 Please check out our examples:
   - [basic library import](https://github.com/tensorflow/models/blob/master/tensorflow_models/tensorflow_models_pypi.ipynb)
-  - [nlp model building](https://github.com/tensorflow/models/blob/master/official/colab/nlp/nlp_modeling_library_intro.ipynb)
+  - [nlp model building](https://github.com/tensorflow/models/blob/master/docs/nlp/index.ipynb)
 to learn how to use a PIP package.
 
 Note that **tf-models-official** may not include the latest changes in the master branch of this