An aws_profile option is added to the AWS ECR login credentials
configuration to allow using shared AWS credentials stored in
a non-default profile.
Signed-off-by: Aaron Browne <aaron0browne@gmail.com>
This adds support for authenticating towards ECR in the docker builder
and docker-push post-processor using them same mechanisms as in the
amazon builders. I.g. access key/secret key, credentials on file,
environment variables, sts tokens or IAM instance roles.