VOL-936 Update protos to latest and mark GetExtValue as NotImplemented

Change-Id: Ic80e8f3cbffa022d0abfe3a0845ebe6b3adfa83f
diff --git a/go.mod b/go.mod
index 25c3697..b8e07f8 100644
--- a/go.mod
+++ b/go.mod
@@ -7,7 +7,7 @@
 	github.com/golang/protobuf v1.3.2
 	github.com/google/uuid v1.1.1
 	github.com/opencord/voltha-lib-go/v3 v3.1.6
-	github.com/opencord/voltha-protos/v3 v3.3.2
+	github.com/opencord/voltha-protos/v3 v3.3.3
 	github.com/phayes/freeport v0.0.0-20180830031419-95f893ade6f2
 	github.com/stretchr/testify v1.4.0
 	google.golang.org/grpc v1.24.0