pulumi instructions should note that both python 2.7 and 3.x (3.6?) are required

[aturley]

orchestration/pulumi/README.md lists required software for setting things up with Pulumi. One of the requirements is "python". Running the commands actually requires both Python 2.7 (for Anisible 2.1.1.0) and Python 3.x.

The instructions should specify that both Python 2.7 and Python 3.x (probably 3.6 or above) must be installed, and that Ansible 2.1.1.0 should be installed under Python 2.7, as should boto.