Allow publishing reports to Github Action Job Summaries

[ianpittwood]

Sometimes I find myself not wanting to publish a comment on my PR for a test report and would rather use Job Summaries to hide reports while still keeping them available. Seeing as the github-test-reporter can already do all the ingesting and formatting of reports, it wouldn't make sense for me to write my own method of doing this. It would be awesome if the tool could be modified to either allow output to stdout so we can redirect the report into the $GITHUB_STEP_SUMMARY environment variable or if an option were added to redirect output there automatically.