When xml and junit test report is enabled plugin doesn't work

[OlegZv]

When xml_tests_report and junit_tests_report is enabled the extension doesn't work, it stuck on the testing stage.

Removing junit_tests_report makes it work again.

:plugins:
  :load_paths:
    - vendor/ceedling/plugins
  :enabled:
    - xml_tests_report
    - junit_tests_report
    - stdout_pretty_tests_report
    - module_generator
    - raw_output_report
    - gcov

[numaru]

This seems fixed by ThrowTheSwitch/Ceedling#324. Since it require the last (and unreleased) version of ceedling, a disclaimer should be appended to the README.md of this repo.