GHA - cron to archive un-used staging deployments

[bign8]

Sometimes, we run out of active versions on the app-engine project and we can't create new staging deploys. It doesn't happen often, but when it does it's pretty annoying.

https://console.cloud.google.com/appengine/versions?project=crucial-alpha-706

It would be kinda cool if we could run a task on some fairly infrequent frequency, to archive old and unused app-engine versions.