Add support for JUnit output in verifier

[gregtyler]

Original Slack thread

The old Ruby verifier supported an option to format the output as JUnit XML (--format=RspecJunitFormatter), which is very helpful when running Pact as part of a larger pipeline since it allows us comb failures from all tests.

It would be great if the new verifier could support JUnit output too.

(NB: there's an existing issue in the Ruby verifier about overwriting output when testing against multiple consumers)

[rholshausen]

/jira ticket

[github-actions[bot]]

👋 Thanks, Jira [PACT-762] ticket created.

[rholshausen]

0.10.3 has been released with a JUnit XML output option