Add E2EE notes to example readme (#189)

Author: bcherry

example/README.md

@@ -37,3 +37,8 @@ This app cannot run on iOS simulator on M1 Macs.
 ```sh
 yarn android
 ```
+
+
+### End-to-End Encryption (E2EE)
+
+This example app demonstrates E2EE functionality using the `useRNE2EEManager` hook. You can enable E2EE by toggling it in the pre-join screen and providing an encryption key. When enabled, all audio and video tracks in the room will be end-to-end encrypted.