* Officially supported Python versions now 3.6 .. 3.8
* fix: Handle changed pypandoc API
* fix: Add auto-mode for project layout (close 12)
* Refactored setup.py access and added some poetry support
* new `release.shiv` task
* releasing: do early and explicit check for pex/shiv
* releasing: use sys.executable for subcalls
* releasing: support 'pex --windows'
* release.pex: handle 3.8 having no more 'm' ABI flag
* release.pex: write archive to dist/, not bin/
* release.pex: ignore any pure wheel (none-any) when it comes to dist renaming
* release.pex: filter out platform tags with a compatible Python ABI before renaming
* git tags: better error reporting when tag splitting fails
* docs: add source to watch dirs when using API docs
* SCM versions: only consider annotated tags, and exclude 'stable'
* tasks requirements: shiv and pex for releasing
* `upload_artifacts()` is now usable from outside a release task