Document alternative fingerprint types

Author: DivineOmega

README.md

@@ -44,4 +44,11 @@ $fingerprint = $connection->fingerprint();
 if ($newConnection->fingerprint() != $fingerprint) {
     throw new Exception('Fingerprint does not match!');
 }
+```
+
+If you wish, you can specify the type of fingerprint you wish to retrieve.
+
+```php
+$md5Fingerprint  = $connection->fingerprint(SSHConnection::FINGERPRINT_MD5); // default
+$sha1Fingerprint = $connection->fingerprint(SSHConnection::FINGERPRINT_SHA1);
 ```