Updated CHANGELOG for 2.2.0
Updated CHANGELOG for 2.2.0

RxSwiftCommunity/RxSwiftExt,RxSwiftCommunity/RxSwift-Ext,tgyhlsb/RxSwiftExt,RxSwiftCommunity/RxSwiftExt,RxSwiftCommunity/RxSwiftExt,tgyhlsb/RxSwiftExt,RxSwiftCommunity/RxSwift-Ext