Log Message:
py-zope.testrunner: updated to 6.3

6.3 (2024-02-07)

- Exit cleanly when using the test runner ``--version`` argument.

- Add new `--xml path` option to write `JUnit`-like XML reports.
  Code comes from `collective.xmltestreport`, but be aware that here `--xml`
  is not a boolean, but expects a path!

- Add support for Python 3.13a3.