golang acme v2 client using nsupdate for the DNS-01 challenge

USAGE:

 go-acme-nsupdate [OPTIONS] HOSTNAME [HOSTNAME ...]            

  for wildcard certs set HOSTNAME to the domainname                                     

  -accountfile string 
        file of account data -- will be auto-created if unset) (default "account.json") 
  -contact string     
        comma separated contact emails to use for new accounts                          
  -ns string          
        DNS server to query for the status of the nsupdate                              
  -nskey string       
        file for the nsupdate key (default "nsupdate.key")                              
  -test               
        run against LetsEncrypt staging, not production servers                         
  -v                  
        enable verbose output / debugging   
  -wild               
        make a wildcard cert