Require `pull_request` trigger to attach comment

[mikepenz]

• do not fail on missing issue number
  • FIX https://github.com/mikepenz/action-junit-report/issues/1178

[github-actions[bot]]

	Tests	Passed ✅	Skipped ⏭️	Failed ❌
Example Pytest Report	4 ran	2 passed	0 skipped	2 failed

	Test	Result
Example Pytest Report	test_sample.test_which_succeeds	✅ pass
Example Pytest Report	test_sample.test_which_fails	❌ failure
Example Pytest Report	test_sample.test_with_error	❌ failure
Example Pytest Report	test_sample.test_with_flaky_success	✅ pass