Elastic CI Stack for AWS v4.0.3

Changed

• Bump docker to 18.09.1 #516 (@lox)
• Bump agent to 3.8.2 #514 (@lox)
• Tunable knob for ASG Cooldown period #495 (@prateek)

Upgrading

Perform a CloudFormation stack update with the following URL:
https://s3.amazonaws.com/buildkite-aws-stack/v4.0.3/aws-stack.yml

If you want to launch a new stack, you can use this link (make sure not to use your production AWS account, create a new one for CI):

Documentation

See the Readme for this release.