Collection playbooks should avoid the - character

[dkolepp]

Current tooling allows you to create - and build - a playbook like: some-test-playbook.yml, but this will not work when used to run that collection playbook:

$> ansible-playbook xyz.abc.some-test-playbook.yml

[ericzolf]

Good point, I knew this for roles, but didn't notice for playbooks. I think, we should just make one recommendation: name everything like Ansible variables (letters, numbers and underscores), and basta.