Merge pull request react-native-webrtc#464 from SnowLew/master

Update the README

README.md

@@ -11,18 +11,32 @@ For more information about **ConnectionService** on Android, please see [Android
 
 ⚠️ **CallKit** and **ConnectionService** are only available on real devices, this library will not work on simulators.
 
-# Demo
+#  Summary
+- [Demo](#Demo)
+- [Installation](#Installation)
+- [Usage](#Usage)
+  - [Constants](#Constants)
+  - [Android Self Managed](#Android-Self-Managed-Mode)
+  - [Methods](#Methods)
+  - [Example](##Example)
+- [PushKit](#PushKit)
+- [Android 11](#Android-11)
+- [Debug](#Debug)
+- [Troubleshooting](#Troubleshooting)
+- [Contributing](#Contributing)
+- [License](#License)
+
 
+# Demo
 A demo of `react-native-callkeep` is available in the [wazo-react-native-demo](https://github.com/wazo-pbx/wazo-react-native-demo) repository.
 
-## Android
+#### Android
 ![Connection Service](docs/pictures/connection-service.jpg)
 
-## iOS
+#### iOS
 ![Connection Service](docs/pictures/call-kit.png)
 
 # Installation
-
 ```sh
 npm install --save react-native-callkeep
 # or
@@ -34,7 +48,7 @@ yarn add react-native-callkeep
 
 # Usage
 
-## Setup
+#### Setup
 
 ```js
 import RNCallKeep from 'react-native-callkeep';
@@ -128,7 +142,7 @@ Alternative on iOS you can perform setup in `AppDelegate.m`. Doing this allows c
       
 `setup` calls internally `registerPhoneAccount` and `registerEvents`.
 
-## Constants
+# Constants
 
 To make passing the right integer into methods easier, there are constants that are exported from the module.
 
@@ -149,7 +163,7 @@ const { CONSTANTS as CK_CONSTANTS, RNCallKeep } from 'react-native-callkeep';
 console.log(CK_CONSTANTS.END_CALL_REASONS.FAILED) // outputs 1
 ```
 
-## Android Self Managed Mode
+# Android Self Managed Mode
 _This feature is available only on Android._
 
 Android supports calling apps running in what's called "Self Managed". This means the apps are able (and required) to provide their own UI for managing calls. This includes both in call UI elements and incoming call notification UI. This method is all or nothing. You can't mix partial elements, such as having a custom in call view, but use the default incoming call UI.
@@ -171,7 +185,7 @@ Self Managed calling apps are an advanced topic, and there are many steps involv
 <uses-permission android:name="android.permission.READ_CALL_LOG" />
 ```
 
-## Methods
+# Methods
 
 ### getInitialEvents
 _This feature is available only on iOS._
@@ -944,7 +958,7 @@ To be able to wake up your application to display the incoming call, you can use
 
 You have to send a push to your application, like with Firebase for Android and with a library supporting PushKit pushes for iOS.
 
-### PushKit
+## PushKit
 
 Since iOS 13, you'll have to report the incoming calls that wakes up your application with a VoIP push. Add this in your `AppDelegate.m` if you're using VoIP pushes to wake up your application :