This commit restricts the allowed versions of the gettext and
fast_gettext gems to preserve compatability with older versions of
Ruby. This became necessary because the gettext-setup gem loosened its
requirements to allow newer versions of those deps, as part of a
modernization effort. We can remove these pins once we only need to
support Ruby 2.5+.
该提问来源于开源项目：puppetlabs/r10k
