docs: add whitelist option for auth.proxy

docs/sources/installation/configuration.md

@@ -444,20 +444,29 @@ false only pre-existing Grafana users will be able to login (if ldap authenticat
 <hr>
 
 ## [auth.proxy]
+
 This feature allows you to handle authentication in a http reverse proxy.
 
 ### enabled
+
 Defaults to `false`
 
 ### header_name
+
 Defaults to X-WEBAUTH-USER
 
 #### header_property
+
 Defaults to username but can also be set to email
 
 ### auto_sign_up
+
 Set to `true` to enable auto sign up of users who do not exist in Grafana DB. Defaults to `true`.
 
+### whitelist
+
+Limit where auth proxy requests come from by configuring a list of IP addresses. This can be used to prevent users spoofing the X-WEBAUTH-USER header.
+
 <hr>
 
 ## [session]