title: Default credentials can not be used to assume new style deployment roles
body: <p>Following <a href="https://docs.aws.amazon.com/cdk/api/latest/docs/pipelines-readme.html" rel="noreferrer">pipelines readme</a> to set up a deployment pipeline, I ran</p>
  <pre><code>$ env CDK_NEW_BOOTSTRAP=1 npx cdk bootstrap \
      --cloudformation-execution-policies arn:aws:iam::aws:policy/AdministratorAccess \
      aws://[ACCOUNT_ID]/us-west-2
  </code></pre>
  <p>to create the necessary roles. I would assume the roles would automatically add sts assume role permissions from my account principle. However, when I run <code>cdk deploy</code> I get the following warning</p>
  <blockquote>
  <p>current credentials could not be used to assume
  'arn:aws:iam::[ACCOUNT_ID]:role/cdk-hnb659fds-file-publishing-role-[ACCOUNT_ID]-us-west-2',
  but are for the right account. Proceeding anyway.</p>
  </blockquote>
  <p>I have root credentials in <code>~/.aws/credentials</code>.</p>
  <p>Looking at the deploy role policy, I don't see any sts permissions. What am I missing?</p>