Remove version cap on PrettyTable
Remove version cap on PrettyTable

This causes the requirements-check job to fail as a result of
uncapping PrettyTable in [1].

[1] https://review.opendev.org/c/openstack/requirements/+/774917

Change-Id: I19c6ad150cca56a6022f9b9b0c9b5d0b7a2cb15d

openstack/openstack-ansible,openstack/openstack-ansible,stackforge/os-ansible-deployment,stackforge/os-ansible-deployment