readme: Add line about SumoLogic plugin
* Feature - Support for provisioning Tasks with ENIs
* Enhancement - Retry failed container image pull operations [#975](https://github.com/aws/amazon-ecs-agent/pull/975)
* Enhancement - Set read and write timeouts for websocket connectons [#993](https://github.com/aws/amazon-ecs-agent/pull/993)
+* Enhancement - Add support for the SumoLogic Docker log driver plugin
+ [#992](https://github.com/aws/amazon-ecs-agent/pull/992)
* Bug - Fixed a memory leak issue when submitting the task state change [#967](https://github.com/aws/amazon-ecs-agent/pull/967)
* Bug - Fixed a race condition where a container can be created twice when agent restarts. [#939](https://github.com/aws/amazon-ecs-agent/pull/939)
* Bug - Fixed an issue where `microsoft/windowsservercore:latest` was not
