This CL is part of many to extend existing acme package functionality to support RFC8555 without breaking existing users of both this client package and CA implementations which haven't caught up to the RFC spec. Updates golang/go#21081 Change-Id: I20eb339ede019930c3482286cd13a3ba6f2b3cd6 Reviewed-on: https://go-review.googlesource.com/c/crypto/+/182937 Run-TryBot: Alex Vaghin <ddos@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>