7.1.0 not Compatible with Android Intercom SDK 15.14 when using JWT

[matt-ergon]

Describe the bug
In the Readme file there is a compatibility table. When using the JWT authentication, this table is no longer correct because it needs at least Android SDK 15.16 (and nor 15.x as stated in the readme file).

To Reproduce
Steps to reproduce the behavior:

1. set Android SDK to 15.14
2. Install Capacitor Intercom Plugin 7.1
3. Use method setUserJwt
4. build for android. -> error

Expected behavior
Update Readme to state this compatibility requirement.