Changelog update for 1.28.1 with volume deletion bug
# Changelog
+## 1.28.1
+* Bug - Fixed a bug where docker volume deletion resulted in nullpointer [#2059](https://github.com/aws/amazon-ecs-agent/pull/2059)
+
## 1.28.0
* Feature - Introduce high density awsvpc tasks support
* Enhancement - Introduce `ECS_CGROUP_CPU_PERIOD` to make cgroup cpu period configurable [@boynux](https://github.com/boynux) [#1941](https://github.com/aws/amazon-ecs-agent/pull/1941)
