Upgrade flutter-webrtc version to 0.2.8.

cloudwebrtc · cloudwebrtc · commit 099ca89aa1b9 · 2020-04-30T18:38:59.000+08:00
diff --git a/pubspec.yaml b/pubspec.yaml
@@ -8,7 +8,7 @@ environment:
 
 dependencies:
   crypto: ^2.1.2
-  flutter_webrtc: ^0.2.6
+  flutter_webrtc: ^0.2.8
   parser_error: ^0.1.1
   sdp_transform: ^0.2.0
   uuid: ^2.0.2
