Fix loadgenerator not all arguments converted during string formatting (

#3)

# Changes

Please provide a brief description of the changes here.

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* [ ] Appropriate documentation updates in the [docs][]
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The error
```
Message: 'skipping checkout, duration:'
Arguments: (1.1302261352539062,)
--- Logging error ---
Traceback (most recent call last):
  File "/usr/local/lib/python3.11/logging/__init__.py", line 1110, in emit
    msg = self.format(record)
          ^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/logging/__init__.py", line 953, in format
    return fmt.format(record)
           ^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/logging/__init__.py", line 687, in format
    record.message = record.getMessage()
                     ^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/logging/__init__.py", line 377, in getMessage
    msg = msg % self.args
          ~~~~^~~~~~~~~~~
TypeError: not all arguments converted during string formatting
Call stack:
  File "/usr/local/lib/python3.11/site-packages/locust/user/users.py", line 176, in run_user
    user.run()
  File "/usr/local/lib/python3.11/site-packages/locust/user/users.py", line 144, in run
    self._taskset_instance.run()
  File "/usr/local/lib/python3.11/site-packages/locust/user/task.py", line 347, in run
    self.execute_next_task()
  File "/usr/local/lib/python3.11/site-packages/locust/user/task.py", line 372, in execute_next_task
    self.execute_task(self._task_queue.pop(0))
  File "/usr/local/lib/python3.11/site-packages/locust/user/task.py", line 493, in execute_task
    task(self.user)
  File "/usr/src/app/locustfile.py", line 145, in checkout_multi
    logging.info("skipping checkout_multi, duration:", duration)
```

src/loadgenerator/locustfile.py

@@ -124,7 +124,7 @@ def checkout(self):
         duration = time.time() - start_time
         # skip checkout if the latency is more than a second
         if (self.skip_checkout(duration)):
-            logging.info("skipping checkout, duration:", duration)
+            logging.info(f"skipping checkout, duration: {duration}")
             return
         checkout_person = random.choice(people)
         checkout_person["userId"] = user
@@ -142,7 +142,7 @@ def checkout_multi(self):
         duration = time.time() - start_time
         # skip checkout if the latency is more than a second
         if (self.skip_checkout(duration)):
-            logging.info("skipping checkout_multi, duration:", duration)
+            logging.info(f"skipping checkout_multi, duration: {duration}")
             return
 
         checkout_person = random.choice(people)