Release 0.1.60

This version doesn't contain changes to the functionality, only to the
development and build workflows:

• Rename master branch to main.

  To adapt your local repository to the new branch name run the following
  commands:

  git branch -m master main
  git fetch origin
  git branch -u origin/main main
  git remote set-head origin -a

• Automatically add changes from CHANGES.md to release descriptions.