Mass rebuild against ruby 3.0

[Lucas Kanashiro <kanashiro@debian.org>]

Hi team,

I have done a mass rebuild of all ruby reverse dependencies against ruby 
3.0, and here are the results:

https://people.debian.org/~kanashiro/ruby3.0/builds/

Please check it out, and let's try to file bugs and get the failing 
packages fixed (filing bugs upstream when needed). In case you want to 
reproduce the build locally you just need to have experimental enabled 
in your build system and install ruby-all-dev from experimental, it will 
build the package against ruby 2.7 and 3.0.

As a reminder, our goal is to kick off this transition after the 
Bullseye release. With all the freezing process starting we can take 
advantage of experimental to stage fixes.

If you find any issue or have any question or concern feel free to reach 
out.

Cheers!

--
Lucas Kanashiro