Since pyyaml 5.1 yaml.load without specifing loader is deprecated
Details: https://msg.pyyaml.org/load
To keep code compatible with older versions of pyyaml
and keep best perfomance CLoader with fallback to Loader is used.
set shorter time to save some space on server. For those artifacts need
to be stored for long time, we can manually press "keep" button in job page.
Also add a CI job to check if all artifacts have set expire time.