note for ubuntu (Azure-Samples#34)

README.md

@@ -30,6 +30,7 @@ The repo includes sample data so it's ready to try end to end. In this sample ap
 - [Azure Developer CLI](https://aka.ms/azure-dev/install)
 - [Python 3+](https://www.python.org/downloads/)
     - **Important**: Python and the pip package manager must be in the path in Windows for the setup scripts to work.
+    - **Important**: Ensure you can run `python --version` from console. On Ubuntu, you might need to run `sudo apt install python-is-python3` to link `python` to `python3`.    
 - [Node.js](https://nodejs.org/en/download/)
 - [Git](https://git-scm.com/downloads)
 - [Powershell 7+ (pwsh)](https://github.com/powershell/powershell) - For Windows users only.