Expand trusted proxies to all non-routable blocks.

Expand `trusted_proxies` to include all non-routable network blocks per RFC 1918

gitlab/gitlab-deployment.yml

@@ -127,7 +127,7 @@ spec:
             gitlab_rails['uploads_directory'] = '/gitlab-data/uploads'
             gitlab_ci['builds_directory'] = '/gitlab-data/builds'
             gitlab_rails['registry_path'] = '/gitlab-registry'
-            gitlab_rails['trusted_proxies'] = ["10.0.0.0/8"]
+            gitlab_rails['trusted_proxies'] = ["10.0.0.0/8","172.16.0.0/12","192.168.0.0/16"]
             prometheus['enable'] = true
             node_exporter['enable'] = true