Update for Kubernetes 1.16+

[jrissler]

Happy to fix any issues / change anything that I didn't do right, was learning Helm 3 at the same time :)

Solves #1

[neoGeneva]

Hey @jrissler, these changes looks pretty straight forward so I'll approve them.

I'm not sure I'll have the time to maintain this project (and I'm not sure anyone's even using it), so if you're keen to maintain it I can transfer ownership, or make you a contributor (I'm not sure which is best,) or I can just keep accepting pull-requests when I have time.

[neoGeneva]

Also, just so you know, this was a total learning project for me to, it was the first (and only time) I've written Go, so the whole thing certainly was an experience!

[jrissler]

@neoGeneva awesome thanks. That's impressive that you were able to put this together and learn Go at the same time!

I still have one more issue to work through - probably work on it next weekend. I don't think it's with your library - though I can't quite prove it's not lol. I ended up temporarily using http01 vs dns01

With a groupName of something like acme.mycompany.com in the ClusterIssuer (or Issuer) - everything goes well up till this error in GC: User "system:serviceaccount:cert-manager:cert-manager" cannot create resource "godaddy" in API group. The API group is it's trying to use is godaddy.acme.mycompany.com - I think this makes sense, somewhere you note it would be useful in case you had multiple resolvers. However not quite sure whether this is a RBAC issue (seems like it), or an issue with GC somewhere that can be resolved there. Any ideas?

I'm happy to help with ownership or contributor, whatever makes sense. I need to get these working for quite a few instances - so will def be in here for awhile and be re-using / keeping updated.