**Description**

Currently when the ECSOperator fails because the ECS task is not in 'success' state it returns a generic message like that in Airflow alerts that doesn't have much value when we want to debug things quickly.

`This task is not in success state {<huge JSON from AWS containing all the ECS task details>}`


**Use case / motivation**

This is to make it faster for people to fix an issue when a task running ECSOperator fails.

**Proposal**

The idea would be to return instead the last lines of logs from Cloudwatch (that are printed above in Airflow logs) so when we receive the alert we know what failed in the ECS task instead of having to go to Airflow logs to find it. This feature would involve changes there I think:
- https://github.com/apache/airflow/blob/2ce6e8de53adc98dd3ae80fa7c74b38eb352bc3a/airflow/providers/amazon/aws/operators/ecs.py#L354
- https://github.com/apache/airflow/blob/2ce6e8de53adc98dd3ae80fa7c74b38eb352bc3a/airflow/providers/amazon/aws/operators/ecs.py#L375


airflow/providers/amazon/aws/operators/ecs.py
:param aws_conn_id: connection id of AWS credentials / region name. If None,
        credential boto3 strategy will be used
        (http://boto3.readthedocs.io/en/latest/guide/configuration.html).
    :type aws_conn_id: str
    :param region_name: region name to use in AWS Hook.
        Override the region_name in connection (if provided)
    :type region_name: str
    :param launch_type: the launch type on which to run your task ('EC2' or 'FARGATE')
    :type launch_type: str
    :param capacity_provider_strategy: the capacity provider strategy to use for the task.
        When capacity_provider_strategy is specified, the launch_type parameter is omitted.
        If no capacity_provider_strategy or launch_type is specified,
        the default capacity provider strategy for the cluster is used.
    :type capacity_provider_strategy: list
    :param group: the name of the task group associated with the task
    :type group: str
    :param placement_constraints: an array of placement constraint objects to use for
        the task
    :type placement_constraints: list
    :param placement_strategy: an array of placement strategy objects to use for
        the task
    :type placement_strategy: list
    :param platform_version: the platform version on which your task is running
    :type platform_version: str
    :param network_configuration: the network configuration for the task
    :type network_configuration: dict
    :param tags: a dictionary of tags in the form of {'tagKey': 'tagValue'}.
    :type tags: dict
    :param awslogs_group: the CloudWatch group where your ECS container logs are stored.
        Only required if you want logs to be shown in the Airflow UI after your job has