I knew you'd read this file. :)

Support for subjectAltName
==========================

easyrsa init-pki
easyrsa --batch build-ca nopass
easyrsa --batch --req-cn=example.com gen-req example.com nopass
easyrsa --batch --subject-alt-name='DNS:example.com,DNS:www.example.com'  \
    sign-req server example.com

https://github.com/OpenVPN/easy-rsa/issues/22#issuecomment-362899370
