How we version and develop modules is something which needs documenting
beyond individual READMEs. For example, [1] covers how hotfixes should
be made.

[1] http://tinyurl.com/yskndvdu, or:
  https://guidebook.devops.uis.cam.ac.uk/en/latest/tutorials/
    automating-gitlab-releases/
    #creating-a-hotfix-for-a-previously-released-version