docs: add pictureInPicture prop's Android guide

docs/pages/component/props.md

@@ -361,6 +361,17 @@ Determine whether the media should played as picture in picture.
 * **false (default)** - Don't not play as picture in picture
 * **true** - Play the media as picture in picture
 
+To use this feature on Android, you must:
+* [Declare PiP support](https://developer.android.com/develop/ui/views/picture-in-picture#declaring) in your AndroidManifest.xml
+* setting `android:supportsPictureInPicture` to `true`
+Example
+```xml
+<activity
+  android:name=".MainActivity"
+  ...
+  android:supportsPictureInPicture="true">
+```
+
 NOTE: Video ads cannot start when you are using the PIP on iOS (more info available at [Google IMA SDK Docs](https://developers.google.com/interactive-media-ads/docs/sdks/ios/client-side/picture_in_picture?hl=en#starting_ads)). If you are using custom controls, you must hide your PIP button when you receive the ```STARTED``` event from ```onReceiveAdEvent``` and show it again when you receive the ```ALL_ADS_COMPLETED``` event.
 
 Platforms: Android, iOS