Added documentation for toggleAudioRouteSpeaker function

Author: vtn-dev-prithipal

README.md

@@ -398,6 +398,16 @@ _This feature is available only on iOS._
 RNCallKeep.checkSpeaker();
 ```
 
+### toggleAudioRouteSpeaker
+
+Update the audio route of Audio Service on Android with a `routeSpeaker` boolean value (`true` if speaker need on, `false` otherwise).
+When Phone call is active, Android control the audio via connection service. so this function help to toggle the audio to Speaker or wired/ear-piece or vice-versa 
+_This feature is available only on Android._
+
+```js
+RNCallKeep.toggleAudioRouteSpeaker(uuid: string, routeSpeaker: boolean);
+```
+
 ### supportConnectionService (async)
 
 Tells if `ConnectionService` is available on the device (returns a boolean).