change namespace to teamspeak3

src/metrics.php

@@ -5,7 +5,7 @@ require_once('help.php'); // provides $help_texts
 
 // initialize the Prometheus registry
 $registry = new \Prometheus\CollectorRegistry(new \Prometheus\Storage\InMemory());
-$namespace = 'ts3';
+$namespace = 'teamspeak3';
 $virtualserver_label_keys = [
     'virtualserver_id',
     'virtualserver_port',