[FSSDK-11723] fix: rubocop failing on ruby 3.0.0

[FarhanAnjum-opti]

Summary

Running rubocop via Bundler is currently failing due to a version conflict between the tsort gem and Ruby 3.0.0.

Test plan

The existing unit tests has to pass.

Issues

FSSDK-11723

[Mat001]

Approved.

Adding comment:
We downgraded Rubocop to a version compatible with Ruby 3.0.0 to avoid runtime errors caused by newer Rubocop releases requiring tsort version 0.2.0, which is not available in Ruby 3.0.0’s bundled standard library. This ensures stable linting support and maintains guaranteed correctness for Ruby 3.0.0 users.

The reason we cannot pin tsort in our Gemfile is that tsort is a default (standard library) gem whose version is tightly coupled to the Ruby version installed and cannot be independently upgraded or overridden by Bundler. Unlike external gems (such as Rubocop), standard gems like tsort come fixed with Ruby itself, so managing their version means managing the Ruby version.

Therefore, the only viable solution to resolve conflicts involving tsort is to downgrade Rubocop to a version that is compatible with the tsort version bundled in Ruby 3.0.0, rather than trying to pin or upgrade tsort itself.