Update JUnit versions used in docs/ITs

Docs

The JUnit artifact versions used in the Surefire configuration examples are quite old which can lead to users misconfiguring Surefire as happened in SUREFIRE-2121.

Using the current artifact versions can prevent such mistakes.

It also signals to the user that the most recent JUnit 4/5 versions are supported by Surefire.

For JUnit 5 the version 5.9.1 should be used in the docs.

For JUnit 4 the version 4.13.2 should be used in the docs.

Integration Tests

4.13.1 and 4.13.2 shall be added to JUnitVersion and covered in JUnit4VersionsIT.

Integration tests that use versions like 4.13.1 or 4.13 shall be updated to use 4.13.2.

Integration tests shall use JUnit 5 artifacts in version 5.9.1 unless a specific other version is needed.