**Description**
The `airflow.models.baseoperator.chain()` is a very useful and convenient way to add sequential task dependencies in DAGs but the function only supports tasks of a `BaseOperator` type.

**Use case / motivation**
Users who create tasks via the `@task` decorator will not be able to use the `chain()` function to apply sequential dependencies that do not share an `XComArg` implicit dependency.

**Are you willing to submit a PR?**
Absolutely. 🚀 

**Related Issues**
None

airflow/models/baseoperator.py
self,
        task_or_task_list: Union[TaskMixin, Sequence[TaskMixin]],
        upstream: bool = False,
        edge_modifier: Optional[EdgeModifier] = None,
    ) -> None:
        """Sets relatives for the task or task list."""
        if not isinstance(task_or_task_list, Sequence):
            task_or_task_list = [task_or_task_list]
        task_list: List["BaseOperator"] = []
        for task_object in task_or_task_list:
            task_object.update_relative(self, not upstream)
            relatives = task_object.leaves if upstream else task_object.roots
            task_list.extend(relatives)
        for task in task_list:
            if not isinstance(task, BaseOperator):
                raise AirflowException(
                    "Relationships can only be set between "
                    "Operators; received {}".format(task.__class__.__name__)
                )
        
        
        dags = {
            task._dag.dag_id: task._dag for task in self.roots + task_list if task.has_dag()  
        }
        if len(dags) > 1:
            raise AirflowException(
                f'Tried to set relationships between tasks in more than one DAG: {dags.values()}'
            )