upgrade to commons-digester3

[car-roll]

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

ping @daniel-beck

• 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

[olivergondza]

I am not a maintainer of this plugin. The code added here is the one suggested in core PR. So +1 on merging this.

[alecharp]

I don't think the official maintainer of the plugin is active anymore on GitHub.

[marekkopecky]

I don't think the official maintainer of the plugin is active anymore on GitHub.

It seems that previous MR #2 was merged by @daniel-beck. Another MR #1 was merged by @olivergondza . Both seems to be active on GitHub.

[daniel-beck]

Both were merged in our (then) project-wide roles as security officer and infra team member, respectively.