add all_timestep line to Trap.py

Author: MostafaGomaa93

PyStemmusScope/bmi/variable_reference.py

@@ -44,6 +44,7 @@ class BmiVariable:
         units="cm s-1",
         grid=0,
         keys=["Trap"],
+        all_timesteps=True,    
     ),
     # soil vars:
     BmiVariable(