Use IPv4 localhost everywhere (or almost everywhere)

roles/matrix-synapse/tasks/ext/mautrix-telegram/setup.yml

@@ -102,7 +102,7 @@
         	proxy_pass http://$backend;
         {% else %}
         	{# Generic configuration for use outside of our container setup #}
-        	proxy_pass http://localhost:8080;
+        	proxy_pass http://127.0.0.1:8080;
         {% endif %}
         }