HOWTO create a new release

Things to do for releasing:

• announce intent to release on gitter
• check for open issues / pull requests that really should be in the release
  • come back when these are done
  • … or ignore them and do another release next week
• check for deprecations "long enough ago" (two months or two releases, whichever is longer)
  • remove affected code
• Do the actual release changeset
  • Run towncrier
    • review history change
    • git rm changes
  • update version number
    • increment as per Semantic Versioning rules
    • remove +dev tag
  • commit it
• prepare pull request to "release" branch
• announce PR on gitter
  • wait for feedback
  • fix problems, if any
• verify that checks succeeded
• acknowledge the release PR
• tag with vVERSION
• push to PyPI
  • python3 setup.py sdist bdist_wheel upload
• announce on gitter
• update version number
  • simply add +dev tag
• prepare pull request back to master
  • acknowledge it