Switch to the master constraint in tox.ini

To releas a new tag for Tempest 2024.2, we modified the
compatible constraint in tox.ini
- https://review.opendev.org/c/openstack/tempest/+/930091

As new tag is released now so we can switch back to the master
constraint in tox.ini.

Change-Id: I20c205c8ac8679f7f202ef854a406973f8f22136
2 files changed