upgrade to commons-digester3

[car-roll]

upgrade to commons-digester3. Follow up of jenkinsci/jenkins#5320

ping @yasu-s

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your master 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

[alecharp]

@yasu-s do you think this PR could be merged and you could cut a release with it? Thank you very much.

[DanWilczyk-Cashplus]

@alecharp, @MRamonLeon, @bitwiseman, @tandibar, @car-roll I was wondering if you are still using this plug-in? If so, did you create your own builds and install onto Jenkins manually?

[alecharp]

@DanWilczyk-Cashplus no we don't. This work was part of an global effort to remove some libraries from Jenkins Core. We tried here to help the official maintainer of the plugin.