Added note for assumed roles
Added note for assumed roles

yinshiua/amazon-ecr-credential-helper,sentientmonkey/amazon-ecr-credential-helper,glassechidna/amazon-ecr-credential-helper,glassechidna/amazon-ecr-credential-helper,sentientmonkey/amazon-ecr-credential-helper,yinshiua/amazon-ecr-credential-helper,digitalfiz/amazon-ecr-credential-helper,digitalfiz/amazon-ecr-credential-helper