Reduce worker count from 4 to 2

We'll be creating a second site instance to allow for rolling restarts, so it makes sense to half this so when we double the requests we'll effectively have 4 workers again.

manage.py

@@ -163,7 +163,7 @@ def run_server(self) -> None:
             "-b", "0.0.0.0:8000",
             "pydis_site.wsgi:application",
             "--threads", "8",
-            "-w", "4",
+            "-w", "2",
             "--max-requests", "1000",
             "--max-requests-jitter", "50",
             "--statsd-host", "graphite.default.svc.cluster.local:8125",