Documentation update

[Bowriverstudio]

After installing volttron-ansible and running the playbook I get the following error:

ansible-galaxy install git+https://github.com/volttron/volttron-ansible.git

ERROR! the role 'volttron.deployment.set_defaults' was not found in /Users/username/Development/iot/experiment-volttron/playbooks/roles:/Users/username/.ansible/roles/volttron-ansible:/Users/username/Development/iot/experiment-volttron/playbooks

The error appears to be in '/Users/username/Development/iot/experiment-volttron/playbooks/install-platform.yml': line 6, column 7, but may
be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:

roles:
- volttron.deployment.set_defaults
^ here

I believe the docs should be updated to:

ansible-galaxy collection install git+https://github.com/volttron/volttron-ansible.git