deps: update react-native-webrtc

This version uses a worker queue for all WebRTC operations in iOS.

package-lock.json

       }
     },
     "react-native-webrtc": {
-      "version": "github:jitsi/react-native-webrtc#b43081ec8357335ab82a2e236c0f6a6ed0b17f9f",
-      "from": "github:jitsi/react-native-webrtc#b43081ec8357335ab82a2e236c0f6a6ed0b17f9f",
+      "version": "github:jitsi/react-native-webrtc#6b0ea124414f6f5b7f234a7d5cec75d30f5f6312",
+      "from": "github:jitsi/react-native-webrtc#6b0ea124414f6f5b7f234a7d5cec75d30f5f6312",
       "requires": {
         "base64-js": "^1.1.2",
         "event-target-shim": "^1.0.5",

package.json

     "react-native-prompt": "1.0.0",
     "react-native-sound": "0.10.9",
     "react-native-vector-icons": "4.4.2",
-    "react-native-webrtc": "github:jitsi/react-native-webrtc#b43081ec8357335ab82a2e236c0f6a6ed0b17f9f",
+    "react-native-webrtc": "github:jitsi/react-native-webrtc#6b0ea124414f6f5b7f234a7d5cec75d30f5f6312",
     "react-redux": "5.0.7",
     "redux": "4.0.0",
     "redux-thunk": "2.2.0",