Update InstancePing.proto (#1)

Modify instance code to instance uuid
diff --git a/register/InstancePing.proto b/register/InstancePing.proto
index 9d9069b..3a332a6 100644
--- a/register/InstancePing.proto
+++ b/register/InstancePing.proto
@@ -32,4 +32,5 @@
 message ServiceInstancePingPkg {
     int32 serviceInstanceId = 1;
     int64 time = 2;
+    string serviceInstanceUUID = 3;
 }