Add highlights and timeline for v2.13.0 (#4225)

Update `CITATION.cff` and changelog for the upcoming release for vers…

…ion 2.13.0 (#4180)

Update citation and changelog for version 2.12 (#3945)

Update the version number and release notes for v2.11.0 (#3695)

Update `scipy.integrate.simps` import (#3704)

Update release date

Add release notes for v2.9 (#3266)

Co-authored-by: Valeriu Predoi <[email protected]>
Co-authored-by: Rémi Kazeroni <[email protected]>

Draft changelog for `v2.8.0` (#3124)

Co-authored-by: Axel Lauer <[email protected]>

up version to 270 in CITATION

Increase ESMValTool version to 2.6.0 (#2738)

* Edit CITATION.cff for version 2.6

* Change date