crypto.SignMessage allows using crypto.Signers that only usefully implement SignMessage to be used for the ACME account key. This would be useful for opening up integrations with opinionated remote signing APIs that don't support pre-hashing. Fixes golang/go#80877 Change-Id: I86bb76cf5865d3d2b8606a6dbd813cbb26447c86 Reviewed-on: https://go-review.googlesource.com/c/crypto/+/815340 Reviewed-by: Daniel McCarney <daniel@binaryparadox.net> Reviewed-by: Filippo Valsorda <filippo@golang.org> Reviewed-by: Sean Liao <sean@liao.dev> LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Carlos Amedee <carlos@golang.org>