[Feature Request] Actions.popAndPush

### Version
Tell us which versions you are using:

- react-native-router-flux v4.2
- react v16.9.0
- react-native v0.61.5

### Feature request

Ok, maybe this is already implemented but I don't know how to set it up. We need **popAndPush** action, I want to push new scene with transition, but to pop scene I am currently in from routing stack, so when I go back from the pushed scene, I don't return to this scene, but to scene before it.

Example:
- I'm in the **Settings** screen
- I click on **Set PIN** button
- **Enter the PIN** scene is pushed
- I enter the PIN, and **Confirm the PIN** scene is pushed
- I change my mind and I press **back** from **Confirm the PIN** scene, but it returns me back to **Enter the PIN** scene, and I wanted to return to the **Settings** scene instead