At least until 2.6.6; quite a chore ;)
The idea is to keep it updated; ideally each PR updates the changelog
otherwise we/I will keep track of the "notable" changes.
The goal would be that once the next release is about to happen, the
changes collected here so far can just be copy-pasted to the release
notes and the top link has to be bumped.
I would define "notable" as user-facing, thus many internal changes
(readme, test suite, etc.) have not been added to give end-users a
clearer focus what may have changed/improved _for them_.
