[DRE-maint] Bug#996297: ruby-ice-nine: FTBFS with ruby3.0: ERROR: Test "ruby3.0" failed: Failure/Error: expect(subject.end).to be_frozen

[s3v]

Dear Maintainer,

I've tried to build your package in a sid chroot environment and no
issues were spotted.
Build on reprodicible-builds also succeeds [1]
(both have ruby-all-dev/1:3.0)

Kind Regards

[1] https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/ruby-ice-nine.html