How should projects depend on ruby2_keywords?

[p]

Hi, we would like to depend on ruby2_keywords in https://github.com/mongodb/mongoid/. To this end I have been researching what we should use in the gemspec for the version range of ruby2_keywords, and I would appreciate an official clarification on this:

• ruby2_keywords readme itself does not provide a version range
• Rails, despite using ruby2_keywords, does not appear to explicitly depend on it. However https://github.com/rails/rails/blob/main/Gemfile.lock contains two Rails dependencies that depend on ruby2_keywords, one of them uses >= 0.0.4 and another one uses ~> 0.0.1.
• Currently ruby2_keywords is at version 0.0.5. Are backwards breaking changes expected? What is preventing the version from being 1.0?

Any thoughts are appreciated.