update doc for v2

README.md

@@ -3,6 +3,8 @@
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 - An ACME protocol client written purely in Shell (Unix shell) language.
 - Full ACME protocol implementation.
+- Support ACME v1 and ACME v2
+- Support ACME v2 wildcard certs
 - Simple, powerful and very easy to use. You only need 3 minutes to learn it.
 - Bash, dash and sh compatible.
 - Simplest shell script for Let's Encrypt free certificate client.