Fix typo

python -> Python

Author: changeworld

includes/iot-pnp-service-python.md

@@ -20,7 +20,7 @@ python --version
 
 The **azure-iot-device** package is published as a PIP.
 
-In your local python environment install the package as follows:
+In your local Python environment install the package as follows:
 
 ```cmd/sh
 pip install azure-iot-device