Add auto-shrink behavior

[sxsx1xsxs]

We are using SwipeCellKit to have one swipe action and trigger the action by dragging pass threshold. The actionsView should auto-shrink if user let go instead of expanding to preferredWidth for the action button. We can define the action's transitionDelegate to achieve threshold as action trigger but not able to achieve the auto-shrink behavior. Thus creating this pull request to adding an auto-shrink attribute in SwipeOptions to achieve this.