v2.3.0: Non-zero exit status on test failure

This release changes the exit code of gotestfmt to a non-zero status if one or more tests fail. This behavior is consistent with the exit status of go test. We have added this to make sure CI doesn't pass on failing tests if users forget to add set -euo pipefail. This behavior can be disabled by passing the -nofail option in the command line.

Thank you to @gabesullice for reporting this issue.