[watcher][caracal] release critical support for new oslo.db

Hi Watchers Ref: https://bugs.launchpad.net/watcher/+bug/2056181 Watcher 12.0.0 RC1 is not compatible with oslo.db 15.0.0 - the test suite has numerous failures as the DB api module has not been updated for the changes in oslo.db to support SQLAlchemy 2.0+. Raising awareness mainly - I can take a look at this but if anyone else with more experience of this transition can help much appreciated. Cheers James