Update installation steps for Windows / Mac OS X for tfjs-node in REA…

…DME.md (#8101)

tfjs-node/README.md

@@ -39,9 +39,9 @@ npm install @tensorflow/tfjs-node-gpu
 yarn add @tensorflow/tfjs-node-gpu
 ```
 
-#### Windows / Mac OS X Requires Python 2.7
+#### Windows / Mac OS X Requires Supported Version of Python
 
-Windows & OSX build support for `node-gyp` requires Python 2.7. Be sure to have this version before installing `@tensorflow/tfjs-node` or `@tensorflow/tfjs-node-gpu`. Machines with Python 3.x will not install the bindings properly.
+Windows & OSX build support for `node-gyp` requires that you have installed a [supported version of Python](https://devguide.python.org/versions/#supported-versions). Be sure to have supported version of Python before installing `@tensorflow/tfjs-node` or `@tensorflow/tfjs-node-gpu`.
 
 *For more troubleshooting on Windows, check out [WINDOWS_TROUBLESHOOTING.md](./WINDOWS_TROUBLESHOOTING.md).*