Dependency on `rouge` is too strict

Rouge 5.0 released in late May and it doesn't seem to have any breaking changes from 4.x that are relevant to Jekyll 4.4: https://github.com/rouge-ruby/rouge/releases

However, Jekyll has a dependency set as rouge >= 3.0, < 5.0 is required., which makes 4.7 the latest version of Rouge that can be used without conflicts. This restriction is probably too strict and could be loosened.