upgrade to commons-digester3

[car-roll]

Upgrade to commons-digester3. downstream 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!
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• Please describe what you did
• Link to relevant issues in GitHub or Jira
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• Ensure you have provided tests - that demonstrates feature works or fixes the issue

[marek-parfianowicz]

In a similar change in the Clover plugin (see jenkinsci/clover-plugin#24), the following snippet was added:

            try {
                digester.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
                digester.setFeature("http://xml.org/sax/features/external-general-entities", false);
                digester.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
                digester.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
            } catch (ParserConfigurationException ex) {
                throw new SAXException("Failed to securely configure xml digester parser", ex);
            }```

I do not see such fragment in this PR for the emma plugin.

[car-roll]

@marek-parfianowicz you're right, that section of code has been added

[marek-parfianowicz]

Looks great! 👍