## Problem
It seems are production-ready cert-manager setup now includes a full
certificate chain. This was not accounted for and the decoder would
error.
## Summary of changes
Change the way we decode certificates to support cert-chains, ignoring
all but the first cert.
This also changes a log line to not use multi-line errors.
~~I have tested this code manually against real certificates/keys, I
didn't want to embed those in a test just yet, not until the cert
expires in 24 hours.~~
afe9b27983