From my perspective as a gem user, I don't want to trust you (or
anyone, nothing personal) to not release the same version with
breaking changes.  If you did, this would mean my previously working
deploy suddenly stopped working when I downloaded the same gem version
on a new machine.  That would be very bad.

Weigh this against the cost of you bumping your version (which as John
pointed out will be automated), and the choice is easy.  Make everyone
bump the version.

It seems that you are overly concerned about your 'broken' code
existing in the wild.  That doesn't really matter.  EVERYBODY releases
broken code.  It's open source, you are doing a great thing by
releasing the code at all!  Congratulations!  If you have a bug, even
in your release metadata; that's what a version bump (and release
notes) are intended to address.  It isn't a problem or a reflection on
you at all.  Frequent releases are good.

However, inadvertently breaking a feature with an innocuous 'fix',
then rereleasing it over the previously-working version (thereby
making the working version unavailable) IS a problem, and people
should be prevented from doing it.

-- Chad