v0.8.26

GH Action for creating releases (#503)

* adds tools for changelog and release management

* use github token

* github_token is used by default, duh

* also check for already-existing higher versions

* workflow

* fixes

* pr feedback

* Update make_changelog.py

Co-authored-by: Philipp Otto <[email protected]>

Co-authored-by: Philipp Otto <[email protected]>