Switch to the master constraint in tox.ini

To releas a new tag for Tempest 2023.2, we modified the
compatible constraint in tox.ini
- https://review.opendev.org/c/openstack/tempest/+/874359/1

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

Change-Id: I431ec42d81c4d2a95d6f541c794607de1f9cadb8
2 files changed