Added a small helper function (LimitVersionTo) to prevent future mistakes.

Bug: angleproject:4168
Change-Id: Ia19312459540adbc2788ad0a5cb3d19ef1ff784f
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1992185
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Ian Elliott <ianelliott@google.com>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>