update version and changelog to v2.7.0
update version and changelog to v2.6.0
update version and changelog to v2.5.2
update version and changelog to v2.5.1
update version and changelog to v2.5.0
update version and changelog to v2.4.1
update version and changelog to v2.4.0
update version and changelog to v2.3.0
update version and docs to v2.2
update docs and version to v2.1