docs: update key features (#237)

## 📜 Description

Added info about `KeyboardAvoidingView` in README.

## 💡 Motivation and Context

There is only blogpost and API page describing `KeyboardAvoidingView`.
For new users it may be difficult to understand that such component is
available out-the-box from the package, so I've decided to add an info
into "Key Features" in README.

## 📢 Changelog

### Docs
- added info about `KeyboardAvoidingView` in README;

## 🤔 How Has This Been Tested?

Tested via github preview.

## 📸 Screenshots (if appropriate):

<img width="674" alt="image"
src="https://github.com/kirillzyusko/react-native-keyboard-controller/assets/22820318/d7c0bb23-40c9-43a4-9cb4-185c7b3bcb98">

## 📝 Checklist

- [x] CI successfully passed

README.md

@@ -13,6 +13,7 @@ Keyboard manager which works in identical way on both iOS and Android.
 - module for changing soft input mode on Android 🤔
 - reanimated support 🚀
 - interactive keyboard dismissing 👆📱
+- re-worked prebuilt components (such as `KeyboardAvoidingView`) 📚
 - works with any navigation library 🧭
 - and more is coming... Stay tuned! 😊