* Add a preview for the "next release" change notes
This change integrates `sphinxcontrib-towncrier` into the docs build.
It uses Towncrier and its configs to render a draft changelog as RST
and injects that into the `changelog.rst` document right above the
older changelog entries using `towncrier-draft-entries` directive.
* Drop the change note from PR #1016
This partially reverts commit 0165dc355d2eb475cf59894d1561efb9b1963a39.
* Use `Not yet released` in the changelog draft
Co-authored-by: Hynek Schlawack <hs@ox.cx>
9169c49966