Update example homeserver address and comment for domain

Closes #327

mautrix_signal/example-config.yaml

@@ -1,8 +1,8 @@
 # Homeserver details
 homeserver:
     # The address that this appservice can use to connect to the homeserver.
-    address: https://example.com
-    # The domain of the homeserver (for MXIDs, etc).
+    address: https://matrix.example.com
+    # The domain of the homeserver (also known as server_name, used for MXIDs, etc).
     domain: example.com
     # Whether or not to verify the SSL certificate of the homeserver.
     # Only applies if address starts with https://

requirements.txt

@@ -4,5 +4,5 @@ commonmark>=0.8,<0.10
 aiohttp>=3,<4
 yarl>=1,<2
 attrs>=19.1
-mautrix>=0.18.6,<0.19
+mautrix>=0.18.9,<0.19
 asyncpg>=0.20,<0.28