Revert "Use victoria stable constraint in tox to release 26.0.0"

This reverts commit f9d31f2c46204abbbef53d3c0ae0f80125878fc9.

Reason for revert: Tempest 26.0.0 is released so we need to switch to master constraints now.

Change-Id: I78780ef88c5f8394ec11b144f148f30b060ed657
1 file changed