Braking release

[simonoff]

Hi all,

Next week i'm planning to release a version 3.0 which will supports only RubyZip 3.0.
But I need to help with making more stable with Ruby 3.x.
Please ping me in such topic if you have issue with Ruby 3.x and have a PR for resolving it. I will merge such change ASAP.

[larskanis]

The roo git master version is working great for me when reading out XLSX files. Hoping for a release compatible with rubyzip-3.0.

[kcollignon]

Looking forward to this release!