Add Alpine Linux 3.21.0

[MarkEWaite]

Add Alpine Linux 3.21.0

• Add Alpine Linux 3.21.0
• Update Oracle Linux test data to 9.5
• Update Amazon Linux 2023 test data
• Update openSUSE tumbleweed to 20241205
• Revert "Bump almalinux (Bump almalinux from 9.4-20240923 to 9.5-20241118 in /src/test/resources/org/jvnet/hudson/plugins/platformlabeler/almalinux/9.4 #1502)"
• Revert "Bump ubi9/ubi (Bump ubi9/ubi from 9.4-1214.1729773476 to 9.5 in /src/test/resources/org/jvnet/hudson/plugins/platformlabeler/registry.access.redhat.com/ubi9/ubi/9.4 #1495)"
• Revert "Bump rockylinux/rockylinux (Bump rockylinux/rockylinux from 9.4.20240523-ubi to 9.5.20241118-ubi in /src/test/resources/org/jvnet/hudson/plugins/platformlabeler/rocky/9.4 #1504)"
• Update Jenkins versions in Jenkinsfile

Testing done

Confirmed that automated tests pass.

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests - that demonstrates feature works or fixes the issue