Fix Ansible dependency and allow 7.1 versions

Using a constraint such as "ansible<=7" is a bad idea, because it will limit the version to exactly 7.0.0 and not even allow 7.0.1.

While fixing this, update to ansible 7.1 as it has only minor core changes.

In the future, we could update to "ansible<8" because 7.(X+1) version updates of Ansible should remain backwards compatible, but in the interest of reproducibility, let's be very conservative.

Ref: https://docs.ansible.com/ansible/devel/reference_appendices/release_and_maintenance.html#id13