private JsonObject getAuthorizationToken(AuthConfig localCredentials) throws IOException, MojoExecutionException {
        HttpPost request = createSignedRequest(localCredentials, new Date());
        return executeRequest(createClient(), request);
    }
Perform extended authentication.  Use the provided credentials as IAM credentials and
get a temporary ECR token.

@param localCredentials IAM id/secret
@return ECR base64 encoded username:password
@throws IOException
@throws MojoExecutionException
src/main/java/io/fabric8/maven/docker/access/ecr/EcrExtendedAuth.java