Updated port to 9168 for web_exporter and config

config/gitlab-monitor.yml.example

 server:
   listen_address: 0.0.0.0
-  listen_port: 4567
+  listen_port: 9168
 
 probes:
   database:

lib/gitlab_monitor/web_exporter.rb

@@ -14,7 +14,7 @@ module GitLab
           config ||= {}
 
           set(:bind, config.fetch(:listen_address, "0.0.0.0"))
-          set(:port, config.fetch(:listen_port, 4567))
+          set(:port, config.fetch(:listen_port, 9168))
         end
 
         def setup_probes(config)