SequentialTaskSet handles task weights in an inconsistent way

[bakhtos]

Prerequisites

• I am using the latest version of Locust
• I am suggesting a new feature, not asking a question

Description

Currently, SequentialTaskSet does not allow its tasks attribute to be a dict, and throws the following error:

if isinstance(value, list):
     new_tasks.extend(value)
else:
     raise ValueError("On SequentialTaskSet the task attribute can only be set to a list")

However, if they weight is provided to the @task decorator, the tasks are actually repeated in the task list according to the weight:

if "locust_task_weight" in dir(value):
      # method decorated with @task
      for _ in range(value.locust_task_weight):
            new_tasks.append(value)

This is inconsistent.
It should be possible to provide task weights also in a dict, with similar repeated insertion into the list.
(Few would probably use it like that, but it removes the inconsistency).