@griffin It's quite confusing, I thought the same thing some moments ago, but the Crypt-LE client doesn't seem to be related to ZeroSSL. Since version 0.36 the mention of ZeroSSL has been removed. See my post in the link for more info.
@mushu 0.36 hasn't been released yet, while the two branches on GitHub have quite recent commits (mostly the development branch). So the client isn't "dead" or something like that, just hasn't released a recent release recently. Perhaps you could ask the author directly? In any case, I think you're safe to keep using 0.35. Many users use ancient versions of certbot b/c Ubuntu or Debian repositories aren't updated. Should be fine.