docs: add changelog for 5.2.0

docs: add changelog for 5.2.0-rc.0

docs: add changelog for 5.1.3

docs: add changelog for 5.2.0-beta.1

docs: add changelog for 5.1.2

docs: add changelog for 5.2.0-beta.0

docs: add changelog for 5.1.1

release: cut the 5.1.0 release

docs: add changelog for 5.1.0-rc.1

docs: add changelog for 5.1.0-rc.0