**Description**

Currently when `ECSOperator` is run, the logs of the ECS task are fetched only when the task is done. That's not so convenient, especially when the task takes some good amount of time. In order to understand what's happening with the task, I need to go to Cloudwatch and search for the tasks logs. It would be good to have some parallel process that could fetch ECS task logs from Cloudwatch and make them visible in a realtime. 

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

I can try, but I need to be guided.

tests/providers/amazon/aws/operators/test_ecs.py
client_mock = mock.Mock()
        self.ecs.arn = 'arn'
        self.ecs.client = client_mock
        client_mock.describe_tasks.return_value = {
            'tasks': [{'containers': [{'name': 'foo', 'lastStatus': 'STOPPED', 'exitCode': 1}]}]
        }
        with pytest.raises(Exception) as ctx:
            self.ecs._check_success_task()
        assert str(ctx.value) == (
            "This task is not in success state - last 10 logs from Cloudwatch:\n1\n2\n3\n4\n5"
        )
        client_mock.describe_tasks.assert_called_once_with(cluster='c', tasks=['arn'])
    @mock.patch.object(ECSOperator, '_last_log_messages', return_value=[])
    def test_check_success_tasks_raises_cloudwatch_logs_empty(self, mock_last_log_messages):
        client_mock = mock.Mock()
        self.ecs.arn = 'arn'
        self.ecs.client = client_mock
        client_mock.describe_tasks.return_value = {
            'tasks': [{'containers': [{'name': 'foo', 'lastStatus': 'STOPPED', 'exitCode': 1}]}]
        }
        with pytest.raises(Exception) as ctx:
            self.ecs._check_success_task()
        assert str(ctx.value) == "This task is not in success state - last 10 logs from Cloudwatch:\n"
        client_mock.describe_tasks.assert_called_once_with(cluster='c', tasks=['arn'])
    def test_check_success_tasks_raises_pending(self):