These challenge types have been deprecated by popular ACME providers due to security issues in the ecosystem. Fixes golang/go#28370 Change-Id: I3270a6f5d3e5fbc53e4347a9a802df5f603c87de Reviewed-on: https://go-review.googlesource.com/c/crypto/+/194658 Run-TryBot: Alex Vaghin <ddos@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>