Make matrix-reminder-bot default to in-container networking

roles/matrix-bot-matrix-reminder-bot/defaults/main.yml

@@ -30,7 +30,7 @@ matrix_bot_matrix_reminder_bot_matrix_user_id: '@{{ matrix_bot_matrix_reminder_b
 # The password that the bot uses to authenticate.
 matrix_bot_matrix_reminder_bot_matrix_user_password: ''
 
-matrix_bot_matrix_reminder_bot_matrix_homeserver_url: '{{ matrix_homeserver_url }}'
+matrix_bot_matrix_reminder_bot_matrix_homeserver_url: 'http://matrix-synapse:8008'
 
 # The timezone to use when creating reminders.
 # Examples: 'Europe/London', 'Etc/UTC'