Change heartbeat date format

inbox.py

@@ -1709,7 +1709,7 @@ def runInboxQueue(projectVersion: str, \
         # heartbeat to monitor whether the inbox queue is running
         heartBeatCtr+=1
         if heartBeatCtr>=10:
-            print('>>> Heartbeat Q:'+str(len(queue))+' '+datetime.datetime.now().strftime("%m/%d/%Y, %H:%M:%S"))
+            print('>>> Heartbeat Q:{:d} {:%F %T}'.format(len(queue), datetime.datetime.now()))
             heartBeatCtr=0
 
         if len(queue)==0: