release: cut the v6.0.0 release

release: cut the v6.0.0-rc.6 release

docs: release notes for the 5.2.10 release

docs: add changelog for the 4.4.7 release

docs: add changelog for 6.0.0-rc.5

docs: add changelog for 6.0.0-rc.4

docs: add changelog for 6.0.0-rc.3

docs: add changelog for 6.0.0-rc.2

docs: add changelog for 6.0.0-rc.1

docs: add changelog for 6.0.0-rc.0