Upgrade to Spring Cloud AWS 2.3

[nickcaballero]

Upgrade to Spring Cloud AWS 2.3, which has moved to https://github.com/awspring/spring-cloud-aws.

[artembilan]

Sure! Good timing!

We can bump the version to 2.5 over here and move it to a new Spring for AWS.
Plus other upgrades like Spring Integration 5.5.

The contribution is welcome: https://github.com/spring-projects/spring-integration/blob/master/CONTRIBUTING.adoc !