Document the process for releasing new versions of Gems

[jrgriffiniii]

In support of https://github.com/samvera/maintenance/issues/137, the following tasks should be documented within this repository:

• A brief overview of semantic versioning
• Updating source code files (e. g. the gemspec, lib/version.rb, ...)
• Updating the changelog
• Creating the pull request before the next patch/minor/major release
• Following the review, approval, and merging of this pull request, the tagging of a new release
• The publishing of the new release to https://rubygems.org/
• The drafting of a new GitHub release using https://docs.github.com/en/repositories/releasing-projects-on-github/about-releases
• Informing the Samvera Community of the new release using Slack and the Google Groups

[jrgriffiniii]

https://github.com/ccmywish/chlog looks desirable as a recommended tool to automating the process of generating changelogs.