Add configuration example for proxy_allowed

Author: James Fargher

config.yml.example

@@ -72,6 +72,10 @@ sshd:
   # Proxy protocol policy ("use", "require", "reject", "ignore"), "use" is the default value
   # Values: https://github.com/pires/go-proxyproto/blob/195fedcfbfc1be163f3a0d507fac1709e9d81fed/policy.go#L20
   proxy_policy: "use"
+  # Proxy allowed IP addresses. Takes precedent over proxy_policy. Disabled by default.
+  # proxy_allowed:
+  #  - "192.168.0.1"
+  #  - "192.168.1.0/24"
   # Address which the server listens on HTTP for monitoring/health checks. Defaults to localhost:9122.
   web_listen: "localhost:9122"
   # Maximum number of concurrent sessions allowed on a single SSH connection. Defaults to 10.