I'm wanting to use the playbooks on Ubuntu 18.04. The changes to make that work seem small:
Bump the latest supported version in roles/common/tasks/main.yml
Add an entry to README.md for Ubuntu 18.04
The dependencies can be simplified since they seem to be satisfied by 18.04 out of the box.
Remove python-software-properties from roles/common/vars/ubuntu.yml
In fact I think we can remove software-properties-common too since that seems to be a dependency for the Ansible installation itself and is covered in the instructions.
I'm wanting to use the playbooks on Ubuntu 18.04. The changes to make that work seem small:
Bump the latest supported version in roles/common/tasks/main.yml
Add an entry to README.md for Ubuntu 18.04
Remove python-software-properties from roles/common/vars/ubuntu.yml
I'll submit a pull request for review.