Remove unused Join callback

src/matrix_rssbot/classes/callbacks/__init__.py

@@ -12,13 +12,11 @@ from nio import (
 
 from .sync import sync_callback
 from .invite import room_invite_callback
-from .join import join_callback
 from .message import message_callback
 from .roommember import roommember_callback
 
 RESPONSE_CALLBACKS = {
     SyncResponse: sync_callback,
-    JoinResponse: join_callback,
 }
 
 EVENT_CALLBACKS = {