DKIM issues (py3)

[blueyed]

I've noticed several issues with the manual DKIM signing:

1. pydkim seems to be abandoned, and is forked into dkimpy (https://launchpad.net/dkimpy)
2. dkimpy has issues with py3, e.g. include_headers has to be a list of byte strings on py3 (https://bugs.launchpad.net/dkimpy/+bug/1776775)

Is it worth having it after all, given that there is https://docs.aws.amazon.com/ses/latest/DeveloperGuide/easy-dkim.html (which is also mentioned in the docs by now)?

Maybe keep it, but document its problems?
As for include_headers expected to be bytes, that might get fixed eventually (or django-ses could cast it), but that's where I started wondering if it should be maintained further after all.