Merge pull request #992 from Unity-Technologies/develop-docs

Make doc specific about Python version

docs/Installation.md

 
 ## Install Python (with Dependencies)
 
-In order to use ML-Agents toolkit, you need Python 3.5 or 3.6 along with
+In order to use ML-Agents toolkit, you need Python 3.6 along with
-**NOTE** If you are using Anaconda and are having trouble with TensorFlow, please see the following [note](https://www.tensorflow.org/install/install_mac#installing_with_anaconda) on how to install TensorFlow in an Anaconda environment. 
+**NOTES**
+- We do not currently support Python 3.7 or Python 3.5.
+- If you are using Anaconda and are having trouble with TensorFlow, please see the following [note](https://www.tensorflow.org/install/install_mac#installing_with_anaconda) on how to install TensorFlow in an Anaconda environment. 
 
 ### Windows Users