When I'm doing it, I version subprojects independently using Git tags, but that's primarily because we mix and match versions in production, which creates need

When I'm doing it, I version subprojects independently using Git tags, but that's primarily because we mix and match versions in production, which creates need to make version numbering semantic. If we were doing continuous delivery, too, I could see there not being much value in messing with independent versioning, semver, whatever. Just make today's date the universal version numbering system for all modules and move along.