Lower the cap of oslo.db to <1.1

oslo.db is capped because setuptools 8 changed the way it handles
requirements lists (see 4bbac4c9bc5bcba6962921369ce7721d2a544aa4).  We
need to cap at a version released from oslo.db's stable/juno branch to
avoid introducing incompatible secondary dependencies into stable
deployments. See https://etherpad.openstack.org/p/cloL2FzTRd for
details.

Change-Id: I78c8f0fb9bec942ebd6c1e375294ffb6494dee8e