Set universal_newlines for renew-certs script
Set universal_newlines for renew-certs script

Using `universal_newlines` is better for Python 2/3 compatibility since
it will return a string and not bytes to ensure it's the same regardless
of the version.

pressbooks/trellis,buluma/trellis,pressbooks/trellis,roots/trellis,roots/bedrock-ansible,buluma/trellis,buluma/trellis,newtonne/trellis,newtonne/trellis,roots/bedrock-ansible,newtonne/trellis,buluma/trellis,roots/trellis