v2.3.6: document draft-12 support

package.json

@@ -1,6 +1,6 @@
 {
   "name": "greenlock",
-  "version": "2.3.5",
+  "version": "2.3.6",
   "description": "Let's Encrypt for node.js on npm",
   "main": "index.js",
   "files": [