Changed `stepValue` to `UIBindingObserver` because it's not target/action based
Changed `stepValue` to `UIBindingObserver` because it's not target/action based

kzaher/RxSwift,ReactiveX/RxSwift,kzaher/RxSwift,ReactiveX/RxSwift,kzaher/RxSwift,kzaher/RxSwift,ReactiveX/RxSwift