added timestamp to target_velocity.py

components/shared/dse_shared_libs/target_velocity.py

@@ -1,10 +1,15 @@
 from dataclasses import dataclass
+from datetime import datetime
 
 
 @dataclass
 class TargetVelocity:
     vin: str
     target_velocity: float
+    timestamp: datetime
 
     def to_dict(self):
-        return self.__dict__
+        return {'vin': self.vin,
+                'target_velocity': self.target_velocity,
+                'timestamp': self.timestamp.timestamp()
+                }