Support for Traefik 2.x

[matt4682]

Traefik 2.0.0 was released earlier this week, and changed the acme.json file enough to break this tool.

Old acme.json New acme.json

From a first glance these are the changes that break this tool:

• Everything is wrapped in another object that's keyed based on the resolver
• SANs is no longer a field in the certificate domain
• The keys for fields inside each certificate object are now lowercase (except the new Store field)