Add Pod info for service mesh protocol (#75)

diff --git a/service-mesh-probe/service-mesh.proto b/service-mesh-probe/service-mesh.proto
index 47dbe36..3e398df 100644
--- a/service-mesh-probe/service-mesh.proto
+++ b/service-mesh-probe/service-mesh.proto
@@ -70,6 +70,9 @@
     // |                                  time_to_last_downstream_tx_byte                                                               |
     //                                                                |              internalResponseLatencyNanos                       |
     int64 internalResponseLatencyNanos = 17;
+
+    repeated KeyStringValuePair sourceInstanceProperties = 18;
+    repeated KeyStringValuePair destInstanceProperties = 19;
 }
 
 enum Protocol {