Bump minimum tempest-lib version

Now we(Tempest team) are migrating common part of Tempest to tempest-lib
for running Tempest-like test on each project repository.
That work requires the latest tempest-lib. So this patch bumps minimum
tempest-lib version.

Change-Id: I516d4119fd200c79a8be4598cbb0d732344e8b75
1 file changed