Integrate RingRTC v2.0.1

app/src/main/java/org/thoughtcrime/securesms/events/WebRtcViewModel.java

@@ -24,6 +24,11 @@ public class WebRtcViewModel {
     RECIPIENT_UNAVAILABLE,
     NO_SUCH_USER,
     UNTRUSTED_IDENTITY,
+
+    // Multiring Hangup States
+    CALL_ACCEPTED_ELSEWHERE,
+    CALL_DECLINED_ELSEWHERE,
+    CALL_ONGOING_ELSEWHERE
   }