Enable ruby3.0 as an alternative interpreter again :)

ruby3.0 3.0.2-1 builds failed on several architectures, and this makes
it impossible to resolve build dependencies for any ruby package on
of those architectures.

Gbp-Dch: full

This reverts commit eca67bee.

* ruby: Drop versioned constraint on apt-listbugs, rbenv and ruby-debian in Breaks.

Changes-By: deb-scrub-obsolete

[ci skip] ruby is uninstallable before ruby-rubygems is actually in the
archive.

Fixes: lintian: uses-debhelper-compat-file
See-also: https://lintian.debian.org/tags/uses-debhelper-compat-file.html

Fixes: lintian: debian-changelog-line-too-long
See-also: https://lintian.debian.org/tags/debian-changelog-line-too-long.html

Fixes: lintian: file-contains-trailing-whitespace
See-also: https://lintian.debian.org/tags/file-contains-trailing-whitespace.html

This reverts commit 528aab38.

The packages from the archive have been used when autopkgtest is
executed, now the generated binary packages will be used.

Thanks Steve Langasek for the patch.

Enable ruby2.5 and ruby2.7