Seeking feedback on default encryption algorithm for V4

[Peter Schober]

* Cantor, Scott <cantor.2 at osu.edu> [2020-02-10 14:31]:
> but I don't think SHA1 is much of a need anymore either.

I'd have to dig up Tom S.'s test script but I'm pretty sure we still
have IDPv2 deployments out there.  And AFAIR those do not support
SHA-2 signatures on metadata (or am I confusing issues here?) so we're
still producing a legacy feed...
-peter