Modify pattern to allow searches using wildcards

grep pattern modified to allow searches using wildcard subdomains *.domain.tld. Keep in mind that using *.domain.tld searches literally for *.domain.tld and in this case * doesn't act as a wildcard. Thanks to @travisjeffery for requesting it and provide a pull a request.

Raised rate limit from 20 to 50

2018-Aug-05: Fix, Let's Encrypt has raised the rate limit to issue certificates for a domain in 7 days from 20 to 50,so I've updated it too.

Updated README to show last options