CI/CD: Cleanup unused test environments
Fix https://pagure.io/waiverdb/issue/248
This PR will cleanup all test environments that were created 1 hour ago
before creating a new test environment.
The following Java methods must be approved to allow the pipeline script
to access the Java DateTime API. For more information about Jenkins
In-process Script Approval, see
<https://jenkins.io/doc/book/managing/script-approval/>.
```
method java.text.DateFormat parse java.lang.String
method java.text.DateFormat setTimeZone java.util.TimeZone
method java.util.Date getTime
```