Old port 22 reference changed

Newer software versions utilize port 122, not port 22, for SSH

Author: ronabop

README.md

@@ -48,7 +48,7 @@ Backup host software requirements are modest: Linux or other modern Unix
 operating system with [rsync][4] v2.6.4 or newer.
 
 The backup host must be able to establish network connections outbound to the
-GitHub appliance over SSH (port 22).
+GitHub appliance over SSH (port 22, or 122 (see below)).
 
 ##### Storage requirements