**Description**

I have noticed that the stable REST API doesn't have the ability to run a task (which is possible from the airflow web interface.
I think it would be nice to have either:
- Run task 
- Run all failing tasks (rerun from point of failure)
this ability for integrations.

**Use case / motivation**

I would like the ability to identify the failing tasks on a specific DAG Run and rerun only them.
I would like to do it remotely (non-interactive) using the REST API.
I could write a script that run only the failing tasks, but I couldn't find a way to "Run" a task, when I have the task instance ID.

**Are you willing to submit a PR?**

Not at this stage

**Related Issues**



tests/api_connexion/schemas/test_task_instance_schema.py
result = set_task_instance_state_form.load(self.current_input)
        expected_result = {
            'dry_run': True,
            'execution_date': dt.datetime(2020, 1, 1, 0, 0, tzinfo=dt.timezone(dt.timedelta(0), '+0000')),
            'include_downstream': True,
            'include_future': True,
            'include_past': True,
            'include_upstream': True,
            'new_state': 'failed',
            'task_id': 'print_the_context',
        }
        assert expected_result == result
    @parameterized.expand(
        [
            ({"task_id": None},),
            ({"include_future": "foo"},),
            ({"execution_date": "NOW"},),
            ({"new_state": "INVALID_STATE"},),
        ]
    )
    def test_validation_error(self, override_data):
        self.current_input.update(override_data)
        with pytest.raises(ValidationError):
            set_task_instance_state_form.load(self.current_input)