Fix renew-certs.py
Fix renew-certs.py

We don't need to deal with bytes and binary modes here. The solution was
to set `universal_newlines=True` on `check_output` to ensure we get back
a string and not bytes.

NicBeltramelli/trellis,newtonne/trellis,NicBeltramelli/trellis,partounian/trellis,jeffstieler/bedrock-ansible,partounian/trellis,roots/bedrock-ansible,NicBeltramelli/trellis,partounian/trellis,partounian/trellis,buluma/trellis,roots/trellis,newtonne/trellis,pressbooks/trellis,newtonne/trellis,NicBeltramelli/trellis,pressbooks/trellis,jeffstieler/bedrock-ansible,jeffstieler/bedrock-ansible,buluma/trellis,roots/bedrock-ansible,roots/trellis,buluma/trellis,buluma/trellis