Document how to use Ansible 2.11 in operators

[asmacdo]

/language ansible

Recently we have released a preview image that uses Ansible 2.11 rather than 2.9. This is big change for Ansible, and 2.11 means full adoption of the new collections pattern. For operator authors, there should be very little difference, but they will need to manually choose the ansible-operator-2.11-preview image in their operator's Dockerfile.

https://quay.io/repository/operator-framework/ansible-operator-2.11-preview