Update links to JUnit pages

[cknoblauch]

The links in the java-junit are outdated, this PR updates them to the latest ones.

References

Submitter checklist

• [X] The PR request is well described and justified, including the body and the references
• [X] The PR title represents the desired changelog entry
• [ ] If the change against WireMock 2 functionality (incompatible with WireMock 3), it is submitted against the 2.x branch
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