Release 1.2.3

Update changelog

Android: Rename `Action.isWithInput` to `Action.isInput`

Readme: Improve documenation of actions and events

Android: Some small code documentation and cleanup

Android: Auto dismiss notifications with input action

Changelog: Add: Android: Use Object.assign instead of spread in object literals

Android: Use Object.assign instead of spread in object literals

Android: Move click code to Notification and Action classes

Android: Bugfix: PendingIntent for input actions must be mutable

CHANGELOG: Add change: Bugfix: Make Actions persistent

Android: Rename NotificationClickActivity to ClickActivity

Android: Bugfix: Make Actions persistent

Next dev version 1.2.3

Release version 1.2.2