metrics: implement ipv6 support

Counterpart to mautrix/python#168

Author: Ma27

mautrix_telegram/config.py

@@ -93,6 +93,7 @@ def do_update(self, helper: ConfigUpdateHelper) -> None:
 
         copy("metrics.enabled")
         copy("metrics.listen_port")
+        copy("metrics.addr")
 
         copy("bridge.username_template")
         copy("bridge.alias_template")

mautrix_telegram/example-config.yaml

@@ -97,6 +97,7 @@ appservice:
 metrics:
     enabled: false
     listen_port: 8000
+    addr: '::'
 
 # Manhole config.
 manhole: