Adding badge for Sanity check (#98)

Author: karmel

README.md

@@ -15,6 +15,7 @@
 | **Linux Py3 CPU**   | [![Status](https://storage.googleapis.com/tensorflow-kokoro-build-badges/addons/ubuntu-py3.svg)](https://storage.googleapis.com/tensorflow-kokoro-build-badges/addons/ubuntu-py3.html) |
 | **Linux Py2 GPU**   | [![Status](https://storage.googleapis.com/tensorflow-kokoro-build-badges/addons/ubuntu-gpu-py2.svg)](https://storage.googleapis.com/tensorflow-kokoro-build-badges/addons/ubuntu-gpu-py2.html) |
 | **Linux Py3 GPU**   | [![Status](https://storage.googleapis.com/tensorflow-kokoro-build-badges/addons/ubuntu-gpu-py3.svg)](https://storage.googleapis.com/tensorflow-kokoro-build-badges/addons/ubuntu-gpu-py3.html) |
+| **Linux Sanity Check**   | [![Status](https://storage.googleapis.com/tensorflow-kokoro-build-badges/addons/ubuntu-sanity.svg)](https://storage.googleapis.com/tensorflow-kokoro-build-badges/addons/ubuntu-sanity.html) |
 
 **TensorFlow Addons** is a repository of contributions that conform to
 well-established API patterns, but implement new functionality